|Rifle, Caliber 5.56 mm, M16|
From top to bottom: M16A1, M16A2, M4A1, M16A4
|Place of origin||United States|
|Used by||See Users|
Communist insurgency in Malaysia
Laotian Civil War
Cambodian Civil War
Rhodesian Bush War
Communist rebellion in the Philippines
Insurgency in Aceh
Salvadoran Civil War
Lebanese Civil War
Invasion of Grenada
Sri Lankan Civil War
Somali Civil War
First Liberian Civil War
Sierra Leone Civil War
Nepalese Civil War
Burundian Civil War
First Congo War
Second Liberian Civil War
War in Afghanistan
War in Darfur
2013 Lahad Datu standoff
Iraqi Civil War (2014–2017)
Syrian Civil War
|Designer||Eugene Stoner (AR-10) |
L. James Sullivan (AR-15)
|No. built||c. 8 million as of 2003|
|Variants||See List of Colt AR-15 and M16 rifle variants|
|Mass||6.37 lb (2.89 kg) (unloaded) |
7.5 lb (3.40 kg) (loaded)
|Length||39.5 in (1,003 mm)|
|Barrel length||20 in (508 mm)|
|Cartridge||5.56×45mm NATO (M193)|
|Action||Gas-operated inline short-stroke piston, rotating bolt|
|Rate of fire||700–950 rounds/min cyclic sustained |
45–60 rounds/min semi-automatic
|Muzzle velocity||3,150 ft/s (960 m/s) (M855A1 round)|
|Effective firing range||550 m (601 yd) (point target) |
800 m (875 yd) (area target)
|Maximum firing range||3,600 m (3,937 yd)|
|Feed system||STANAG magazine |
20-round detachable box magazine:
0.211 lb (96 g) empty / 0.738 lb (335 g) full
30-round detachable box magazine:
0.257 lb (117 g) empty / 1.06 lb (480 g) full)
Beta C-Mag 100-round double-lobed drum:
2.20 lb (1,000 g) empty / 4.81 lb (2,180 g) full)
|Sights||Iron sights or various optics|
The M16 rifle, officially designated Rifle, Caliber 5.56 mm, M16, is a family of military rifles adapted from the ArmaLite AR-15 rifle for the United States military. The original M16 rifle was a 5.56mm automatic rifle with a 20-round magazine.
In 1964, the M16 entered US military service and the following year was deployed for jungle warfare operations during the Vietnam War. In 1969, the M16A1 replaced the M14 rifle to become the US military's standard service rifle. The M16A1 improvements include a bolt-assist, chrome-plated bore and a 30-round magazine.
In 1983, the US Marine Corps adopted the M16A2 rifle and the US Army adopted it in 1986. The M16A2 fires the improved 5.56×45mm NATO (M855/SS109) cartridge and has a newer adjustable rear sight, case deflector, heavy barrel, improved handguard, pistol grip and buttstock, as well as a semi-auto and three-round burst fire selector. Adopted in July 1997, the M16A4 is the fourth generation of the M16 series. It is equipped with a removable carrying handle and Picatinny rail for mounting optics and other ancillary devices.
The M16 has also been widely adopted by other armed forces around the world. Total worldwide production of M16s is approximately 8 million, making it the most-produced firearm of its 5.56 mm caliber. The US military has largely replaced the M16 in frontline combat units with a shorter and lighter version, the M4 carbine.
In 1928, a U.S. Army 'Caliber Board' conducted firing tests at Aberdeen Proving Grounds and recommended transitioning to smaller caliber rounds, mentioning in particular the .27. Largely in deference to tradition, this recommendation was ignored and the Army referred to the .30 caliber as "full sized" for the next 35 years. After World War II, the United States military started looking for a single automatic rifle to replace the M1 Garand, M1/M2 Carbines, M1918 Browning Automatic Rifle, M3 "Grease Gun" and Thompson submachine gun. However, early experiments with select-fire versions of the M1 Garand proved disappointing. During the Korean War, the select-fire M2 carbine largely replaced the submachine gun in US service and became the most widely used carbine variant. However, combat experience suggested that the .30 Carbine round was under-powered. American weapons designers concluded that an intermediate round was necessary, and recommended a small-caliber, high-velocity cartridge.
However, senior American commanders having faced fanatical enemies and experienced major logistical problems during WWII and the Korean War, insisted that a single powerful .30 caliber cartridge be developed, that could not only be used by the new automatic rifle, but by the new general-purpose machine gun (GPMG) in concurrent development. This culminated in the development of the 7.62×51mm NATO cartridge.
The U.S. Army then began testing several rifles to replace the obsolete M1 Garand. Springfield Armory's T44E4 and heavier T44E5 were essentially updated versions of the Garand chambered for the new 7.62 mm round, while Fabrique Nationale submitted their FN FAL as the T48. ArmaLite entered the competition late, hurriedly submitting several AR-10 prototype rifles in the fall of 1956 to the U.S. Army's Springfield Armory for testing. The AR-10 featured an innovative straight-line barrel/stock design, forged aluminum alloy receivers and with phenolic composite stocks. It had rugged elevated sights, an oversized aluminum flash suppressor and recoil compensator, and an adjustable gas system. The final prototype featured an upper and lower receiver with the now-familiar hinge and takedown pins, and the charging handle was on top of the receiver placed inside of the carry handle. For a 7.62mm NATO rifle, the AR-10 was incredibly lightweight at only 6.85 lb empty. Initial comments by Springfield Armory test staff were favorable, and some testers commented that the AR-10 was the best lightweight automatic rifle ever tested by the Armory. In the end the U.S. Army chose the T44 now named M14 rifle which was an improved M1 Garand with a 20-round magazine and automatic fire capability. The U.S. also adopted the M60 general purpose machine gun (GPMG). Its NATO partners adopted the FN FAL and HK G3 rifles, as well as the FN MAG and Rheinmetall MG3 GPMGs.
The first confrontations between the AK-47 and the M14 came in the early part of the Vietnam War. Battlefield reports indicated that the M14 was uncontrollable in full-auto and that soldiers could not carry enough ammunition to maintain fire superiority over the AK-47. And, while the M2 carbine offered a high rate of fire, it was under-powered and ultimately outclassed by the AK-47. A replacement was needed: a medium between the traditional preference for high-powered rifles such as the M14, and the lightweight firepower of the M2 Carbine.
As a result, the Army was forced to reconsider a 1957 request by General Willard G. Wyman, commander of the U.S. Continental Army Command (CONARC) to develop a .223-inch caliber (5.56 mm) select-fire rifle weighing 6 lb (2.7 kg) when loaded with a 20-round magazine. The 5.56 mm round had to penetrate a standard U.S. helmet at 500 yards (460 meters) and retain a velocity in excess of the speed of sound, while matching or exceeding the wounding ability of the .30 Carbine cartridge.
This request ultimately resulted in the development of a scaled-down version of the Armalite AR-10, named ArmaLite AR-15 rifle. In the late 1950s, designer Eugene Stoner was completing his work on the AR-15. The AR-15 used .22-caliber bullets, which destabilized when they hit a human body, as opposed to the .30 round, which typically passed through in a straight line. The smaller caliber meant that it could be controlled in autofire due the reduced recoil. Being almost one-third the weight of the .30 meant that the soldier could sustain fire for longer with the same load. Due to design innovations, the AR-15 could fire 600 to 700 rounds a minute with an extremely low jamming rate. Parts were stamped out, not hand-machined, so could be mass-produced, and the stock was plastic to reduce weight.
In 1958, the Army's Combat Developments Experimentation Command ran experiments with small squads in combat situations using the M14, AR-15, and another rifle designed by Winchester. The resulting study recommended adopting a lightweight rifle like the AR-15. In response, the Army declared that all rifles and machine guns should use the same ammunition, and ordered full production of the M-14. However, advocates for the AR-15 gained the attention of Air Force Chief of Staff General Curtis LeMay. After testing the AR-15 with the ammunition manufactured by Remington that Armalite and Colt recommended, the Air Force declared that the AR-15 was its 'standard model' and ordered 8,500 rifles and 8.5 million rounds. Advocates for the AR-15 in the Defense Advanced Research Projects Agency acquired 1,000 Air Force AR-15s and shipped them to be tested by the Army of the Republic of Vietnam (ARVN). The South Vietnam soldiers issued glowing reports of the weapon's reliability, recording zero broken parts while firing 80,000 rounds in one stage of testing, and requiring only two replacement parts for the 1,000 weapons over the entire course of testing. The report of the experiment recommended that the U.S. provide the AR-15 as the standard rifle of the ARVN, but Admiral Harry Felt, then Commander in Chief, Pacific Forces, rejected the recommendations on the advice of the U.S. Army.
Throughout 1962 and 1963, the U.S. military extensively tested the AR-15. Positive evaluations emphasized its lightness, "lethality", and reliability. However, the Army Materiel Command criticized its inaccuracy at longer ranges and lack of penetrating power at higher ranges. In early 1963, the U.S. Special Forces asked, and was given permission, to make the AR-15 its standard weapon. Other users included Army Airborne units in Vietnam and some units affiliated with the Central Intelligence Agency. As more units adopted the AR-15, Secretary of the Army Cyrus Vance ordered an investigation into why the weapon had been rejected by the Army. The resulting report found that Army Materiel Command had rigged the previous tests, selecting tests that would favor the M14 and choosing match grade M14s to compete against AR-15s out of the box. At this point, the bureaucratic battle lines were well-defined, with the Army ordnance agencies opposed to the AR-15 and the Air Force and civilian leadership of the Defense Department in favor.
In January 1963, Secretary of Defense Robert McNamara concluded that the AR-15 was the superior weapon system and ordered a halt to M14 production. In late 1963, the Defense Department began mass procurement of rifles for the Air Force and special Army units. Secretary McNamara designated the Army as the procurer for the weapon with the Department, which allowed the Army ordnance establishment to modify the weapon as they wished. The first modification was the additions of a "manual bolt closure," allowing a soldier to ram in a round if it failed to seat properly. The Air Force, which was buying the rifle, and the Marine Corps, which had tested it both objected to this addition, with the Air Force noting, "During three years of testing and operation of the AR-15 rifle under all types of conditions the Air Force has no record of malfunctions that could have been corrected by a manual bolt closing device." They also noted that the closure added weight and complexity, reducing the reliability of the weapon. Colonel Howard Yount, who managed the Army procurement, would later state the bolt closure was added after direction from senior leadership, rather than as a result of any complaint or test result, and testified about the reasons: "the M-1, the M-14, and the carbine had always had something for the soldier to push on; that maybe this would be a comforting feeling to him, or something."
After modifications, the new redesigned rifle was subsequently adopted as the M16 Rifle. "(The M16) was much lighter compared to the M14 it replaced, ultimately allowing soldiers to carry more ammunition. The air-cooled, gas-operated, magazine-fed assault rifle was made of steel, aluminum alloy and composite plastics, truly cutting-edge for the time. Designed with full and semi-automatic capabilities, the weapon initially did not respond well to wet and dirty conditions, sometimes even jamming in combat. After a few minor modifications, the weapon gained in popularity among troops on the battlefield."
Despite its early failures the M16 proved to be a revolutionary design and stands as the longest continuously serving rifle in US military history. It has been adopted by many US allies and the 5.56×45mm NATO cartridge has become not only the NATO standard, but "the standard assault-rifle cartridge in much of the world." It also led to the development of small-caliber high-velocity service rifles by every major army in the world. It is a benchmark against which other assault rifles are judged.
M16s were produced by Colt until the late 1980s, when FN Herstal began to manufacture them.
In July 1960, General Curtis LeMay was impressed by a demonstration of the ArmaLite AR-15. In the summer of 1961, General LeMay was promoted to U.S. Air Force, Chief of Staff, and requested 80,000 AR-15s. However, General Maxwell D. Taylor, Chairman of the Joint Chiefs of Staff, advised President John F. Kennedy that having two different calibers within the military system at the same time would be problematic and the request was rejected. In October 1961, William Godel, a senior man at the Advanced Research Projects Agency, sent 10 AR-15s to South Vietnam. The reception was enthusiastic, and in 1962 another 1,000 AR-15s were sent. United States Army Special Forces personnel filed battlefield reports lavishly praising the AR-15 and the stopping-power of the 5.56 mm cartridge, and pressed for its adoption.
The damage caused by the 5.56 mm bullet was originally believed to be caused by "tumbling" due to the slow 1 turn in 14-inch (360 mm) rifling twist rate. However, any pointed lead core bullet will "tumble" after penetration in flesh, because the center of gravity is towards the rear of the bullet. The large wounds observed by soldiers in Vietnam were actually caused by bullet fragmentation created by a combination of the bullet's velocity and construction. These wounds were so devastating, that the photographs remained classified into the 1980s.
However, despite overwhelming evidence that the AR-15 could bring more firepower to bear than the M14, the Army opposed the adoption of the new rifle. U.S. Secretary of Defense Robert McNamara now had two conflicting views: the ARPA report favoring the AR-15 and the Army's position favoring the M14. Even President Kennedy expressed concern, so McNamara ordered Secretary of the Army Cyrus Vance to test the M14, the AR-15 and the AK-47. The Army reported that only the M14 was suitable for service, but Vance wondered about the impartiality of those conducting the tests. He ordered the Army Inspector General to investigate the testing methods used; the Inspector General confirmed that the testers were biased towards the M14.
In January 1963, Secretary McNamara received reports that M14 production was insufficient to meet the needs of the armed forces and ordered a halt to M14 production. At the time, the AR-15 was the only rifle that could fulfill a requirement of a "universal" infantry weapon for issue to all services. McNamara ordered its adoption, despite receiving reports of several deficiencies, most notably the lack of a chrome-plated chamber.
After modifications (most notably, the charging handle was re-located from under the carrying handle like AR-10 to the rear of the receiver), the new redesigned rifle was renamed the Rifle, Caliber 5.56 mm, M16. Inexplicably, the modification to the new M16 did not include a chrome-plated barrel. Meanwhile, the Army relented and recommended the adoption of the M16 for jungle warfare operations. However, the Army insisted on the inclusion of a forward assist to help push the bolt into battery in the event that a cartridge failed to seat into the chamber. The Air Force, Colt and Eugene Stoner believed that the addition of a forward assist was an unjustified expense. As a result, the design was split into two variants: the Air Force's M16 without the forward assist, and the XM16E1 with the forward assist for the other service branches.
In November 1963, McNamara approved the U.S. Army's order of 85,000 XM16E1s; and to appease General LeMay, the Air Force was granted an order for another 19,000 M16s. In March 1964, the M16 rifle went into production and the Army accepted delivery of the first batch of 2,129 rifles later that year, and an additional 57,240 rifles the following year.
In 1964, the Army was informed that DuPont could not mass-produce the IMR 4475 stick powder to the specifications demanded by the M16. Therefore, Olin Mathieson Company provided a high-performance ball propellant. While the Olin WC 846 powder achieved the desired 3,300 ft (1,000 m) per second muzzle velocity, it produced much more fouling, that quickly jammed the M16s action (unless the rifle was cleaned well and often).
In March 1965, the Army began to issue the XM16E1 to infantry units. However, the rifle was initially delivered without adequate cleaning kits or instructions because Colt had claimed the M16 was self-cleaning. As a result, reports of stoppages in combat began to surface. The most severe problem was known as "failure to extract"—the spent cartridge case remained lodged in the chamber after the rifle was fired. Documented accounts of dead U.S. troops found next to disassembled rifles eventually led to a Congressional investigation.
We left with 72 men in our platoon and came back with 19, Believe it or not, you know what killed most of us? Our own rifle. Practically every one of our dead was found with his (M16) torn down next to him where he had been trying to fix it.
In February 1967, the improved XM16E1 was standardized as the M16A1. The new rifle had a chrome-plated chamber and bore to eliminate corrosion and stuck cartridges and other, minor, modifications. New cleaning kits, powder solvents and lubricants were also issued. Intensive training programs in weapons cleaning were instituted including a comic book-style operations manual. As a result, reliability problems greatly diminished and the M16A1 rifle achieved widespread acceptance by U.S. troops in Vietnam.
During the early part of its career, the M16 had a reputation for poor reliability and a malfunction rate of two per 1000 rounds fired. The M16's action works by passing high pressure propellant gasses tapped from the barrel down a tube and into the carrier group within the upper receiver, and is commonly referred to as a "direct impingement gas system". The gas goes from the gas tube, through the bolt carrier key, and into the inside of the carrier where it expands in a donut shaped gas cylinder. Because the bolt is prevented from moving forward by the barrel, the carrier is driven to the rear by the expanding gases and thus converts the energy of the gas to movement of the rifle's parts. The back part of the bolt forms a piston head and the cavity in the bolt carrier is the piston sleeve. It is more correct to call it an "internal piston" system."
This design is much lighter and more compact than a gas-piston design. However, this design requires that combustion byproducts from the discharged cartridge be blown into the receiver as well. This accumulating carbon and vaporized metal build-up within the receiver and bolt-carrier negatively affects reliability and necessitates more intensive maintenance on the part of the individual soldier. The channeling of gasses into the bolt carrier during operation increases the amount of heat that is deposited in the receiver while firing the M16 and causes essential lubricant to be "burned off". This requires frequent and generous applications of appropriate lubricant. Lack of proper lubrication is the most common source of weapon stoppages or jams.
The original M16 fared poorly in the jungles of Vietnam and was infamous for reliability problems in the harsh environment. As a result, it became the target of a Congressional investigation. The investigation found that:
- The M16 was billed as self-cleaning (when no weapon is or ever has been).
- The M16 was issued to troops without cleaning kits or instruction on how to clean the rifle.
- The M16 and 5.56×45mm cartridge was tested and approved with the use of a DuPont IMR8208M extruded powder, that was switched to Olin Mathieson WC846 ball powder which produced much more fouling, that quickly jammed the action of the M16 (unless the gun was cleaned well and often).
- The M16 lacked a forward assist (rendering the rifle inoperable when it jammed).
- The M16 lacked a chrome-plated chamber, which allowed corrosion problems and contributed to case extraction failures (which was considered the most severe problem and required extreme measures to clear, such as inserting the cleaning-rod down the barrel and knocking the spent cartridge out).
When these issues were addressed and corrected by the M16A1, the reliability problems decreased greatly. According to a 1968 Department of Army report, the M16A1 rifle achieved widespread acceptance by U.S. troops in Vietnam. "Most men armed with the M16 in Vietnam rated this rifle's performance high, however, many men entertained some misgivings about the M16's reliability. When asked what weapon they preferred to carry in combat, 85 percent indicated that they wanted either the M16 or its [smaller]carbine-length version, the XM177E2." Also "the M14 was preferred by 15 percent, while less than one percent wished to carry either the Stoner rifle, the AK-47, the carbine or a pistol." In March 1970, the "President's Blue Ribbon Defense Panel" concluded that the issuance of the M16 saved the lives of 20,000 U.S. servicemen during the Vietnam War, who would have otherwise died had the M14 remained in service. However, the M16 rifle's reputation continues to suffer.
After the introduction of the M4 Carbine, it was found that the shorter barrel length of 14.5 inches also has a negative effect on reliability, as the gas port is located closer to the chamber than the gas port of the standard length M16 rifle: 7.5 inches instead of 13 inches. This affects the M4's timing and increases the amount of stress and heat on the critical components, thereby reducing reliability. In a 2002 assessment the USMC found that the M4 malfunctioned three times more often than the M16A4 (the M4 failed 186 times for 69,000 rounds fired, while the M16A4 failed 61 times). Thereafter, the Army and Colt worked to make modifications to the M4s and M16A4s in order to address the problems found. In tests conducted in 2005 and 2006 the Army found that on average, the new M4s and M16s fired approximately 5,000 rounds between stoppages.
In December 2006, the Center for Naval Analyses (CNA) released a report on U.S. small arms in combat. The CNA conducted surveys on 2,608 troops returning from combat in Iraq and Afghanistan over the past 12 months. Only troops who had fired their weapons at enemy targets were allowed to participate. 1,188 troops were armed with M16A2 or A4 rifles, making up 46 percent of the survey. 75 percent of M16 users (891 troops) reported they were satisfied with the weapon. 60 percent (713 troops) were satisfied with handling qualities such as handguards, size, and weight. Of the 40 percent dissatisfied, most were with its size. Only 19 percent of M16 users (226 troops) reported a stoppage, while 80 percent of those that experienced a stoppage said it had little impact on their ability to clear the stoppage and re-engage their target. Half of the M16 users never experienced failures of their magazines to feed. 83 percent (986 troops) did not need their rifles repaired while in theater. 71 percent (843 troops) were confident in the M16's reliability, defined as level of soldier confidence their weapon will fire without malfunction, and 72 percent (855 troops) were confident in its durability, defined as level of soldier confidence their weapon will not break or need repair. Both factors were attributed to high levels of soldiers performing their own maintenance. 60 percent of M16 users offered recommendations for improvements. Requests included greater bullet lethality, new-built instead of rebuilt rifles, better quality magazines, decreased weight, and a collapsible stock. Some users recommended shorter and lighter weapons such as M4 carbine. Some issues have been addressed with the issuing of the Improved STANAG magazine in March 2009, and the M855A1 Enhanced Performance Round in June 2010.
In early 2010, two journalists from The New York Times spent three months with soldiers and Marines in Afghanistan. While there, they questioned around 100 infantry troops about the reliability of their M16 rifles, as well as the M4 carbine. The troops did not report reliability problems with their rifles. While only 100 troops were asked, they engaged in daily fighting in Marja, including least a dozen intense engagements in Helmand Province, where the ground is covered in fine powdered sand (called "moon dust" by troops) that can stick to firearms. Weapons were often dusty, wet, and covered in mud. Intense firefights lasted hours with several magazines being expended. Only one soldier reported a jam when his M16 was covered in mud after climbing out of a canal. The weapon was cleared and resumed firing with the next chambered round. Furthermore, the Marine Chief Warrant Officer responsible for weapons training and performance of the Third Battalion, Sixth Marines, reported that "We've had nil in the way of problems; we've had no issues", with his battalion's 350 M16s and 700 M4s.
The M16 is a lightweight, 5.56 mm, air-cooled, gas-operated, magazine-fed assault rifle, with a rotating bolt. The M16's receivers are made of 7075 aluminum alloy, its barrel, bolt, and bolt carrier of steel, and its handguards, pistol grip, and buttstock of plastics.
The M16A1 was especially lightweight at 7.9 pounds (3.6 kg) with a loaded 30-round magazine. This was significantly less than the M14 that it replaced at 10.7 pounds (4.9 kg) with a loaded 20-round magazine. It is also lighter when compared to the AKM's 8.3 pounds (3.8 kg) with a loaded 30-round magazine.
The M16A2 weighs 8.8 lb (4.0 kg) loaded with a 30-round magazine, because of the adoption of a thicker barrel profile. The thicker barrel is more resistant to damage when handled roughly and is also slower to overheat during sustained fire. Unlike a traditional "bull" barrel that is thick its entire length, the M16A2's barrel is only thick forward of the handguards. The barrel profile under the handguards remained the same as the M16A1 for compatibility with the M203 grenade launcher.
Early model M16 barrels had a rifling twist of 4 grooves, right hand twist, 1 turn in 14 inches (1:355.6 mm) bore – as it was the same rifling used by the .222 Remington sporting round. This was shown to make the light .223 Remington bullet yaw in flight at long ranges and it was soon replaced. Later models had an improved rifling with 6 grooves, right hand twist, 1 turn in 12 inches (1:304.8 mm) for increased accuracy and was optimized for use with the standard U.S. M193 cartridge. Current models are optimized for the heavier NATO SS109 bullet and have 6 grooves, right hand twist, 1 turn in 7 in (1:177.8 mm). Weapons designed to accept both the M193 or SS109 rounds (like civilian market clones) usually have a 6-groove, right hand twist, 1 turn in 9 inches (1:228.6 mm) bore, although 1:8 inches and 1:7 inches twist rates are available as well.
"The (M16's) Stoner system provides a very symmetric design that allows straight line movement of the operating components. This allows recoil forces to drive straight to the rear. Instead of connecting or other mechanical parts driving the system, high pressure gas performs this function, reducing the weight of moving parts and the rifle as a whole." The M16's straight-line recoil design, where the recoil spring is located in the stock directly behind the action, and serves the dual function of operating spring and recoil buffer. The stock being in line with the bore also reduces muzzle rise, especially during automatic fire. Because recoil does not significantly shift the point of aim, faster follow-up shots are possible and user fatigue is reduced. Also, current model M16 flash-suppressors also act as compensators to reduce recoil further.
|Velocity||5.1 ft/s (1.6 m/s)|
|Energy||3.2 ft⋅lb (4.3 J)|
Notes: Free recoil is mathematical equation calculated by using the rifle weight, bullet weight, muzzle velocity, and charge weight. It is that which would be measured if the rifle were fired suspended from strings, free to recoil. A rifle's perceived recoil is also dependent on many other factors which are not readily quantified.
The M16's most distinctive ergonomic feature is the carrying handle and rear sight assembly on top of the receiver. This is a by-product of the original design, where the carry handle served to protect the charging handle. As the line of sight is 2.5 in (63.5 mm) over the bore, the M16 has an inherent parallax problem. At closer ranges (typically inside 15–20 meters), the shooter must compensate by aiming high to place shots where desired. The M16 has a 500 mm (19.75 inches) sight radius. The M16 uses an L-type flip, aperture rear sight and it is adjustable with two settings: 0 to 300 meters and 300 to 400 meters. The front sight is a post adjustable for elevation in the field. The rear sight can be adjusted in the field for windage. The sights can be adjusted with a bullet tip or pointed tool, as troops are trained to zero their own rifles. The sight picture is the same as the M14, M1 Garand, M1 Carbine and the M1917 Enfield. The M16 also has a "Low Light Level Sight System", which includes a front sight post with a weak light source provided by tritium radioluminescence in an embedded small glass vial and a larger aperture rear sight.
The M16 can also mount a scope on the carrying handle. With the advent of the M16A2, a new fully adjustable rear sight was added, allowing the rear sight to be dialed in for specific range settings between 300 and 800 meters and to allow windage adjustments without the need of a tool or cartridge. Modern versions such as M16A4 have a detachable carrying handle and use Picatinny rails, which allows for the use of various scopes and sighting devices. The current U.S. Army and Air Force issue M4 Carbine comes with the M68 Close Combat Optic and Back-up Iron Sight. The U.S. Marine Corps uses the ACOG Rifle Combat Optic and the U.S. Navy uses EOTech Holographic Weapon Sight.
Range and accuracy
The M16 rifle is considered to be very accurate. Its light recoil, high-velocity and flat trajectory allow shooters to take head shots out to 300 meters. Newer M16s use the newer M855 cartridge increasing their effective range to 600 meters. They are more accurate than their predecessors and are capable of shooting 1–3-inch groups at 100 yards. "In Fallujah, [Iraq] Marines with ACOG-equipped M16A4s created a stir by taking so many head shots that until the wounds were closely examined, some observers thought the insurgents had been executed." The newest M855A1 EPR cartridge is even more accurate and during testing "...has shown that, on average, 95 percent of the rounds will hit within an 8 × 8-inch target at 600 meters."
|Effective*||Horizontal**||Lethal***||Maximum****||10 shot group
@ 100 meters
|10 shot group |
@ 300 meters
|12.6 in |
Note *: The effective range of a firearm is the maximum distance at which a weapon may be expected to be accurate and achieve the desired effect.
Note **: The horizontal range is the distance traveled by a bullet, fired from the rifle at a height of 1.6 meters and 0° elevation, until the bullet hits the ground.
Note ***: The lethal range is the maximum range of a small-arms projectile, while still maintaining the minimum energy required to put a man out of action, which is generally believed to be 15 kilogram-meters (108 ft.-Ibs.). This is the equivalent of the muzzle energy of a .22LR handgun.
Note ****: The maximum range of a small-arms projectile is attained at about 30° elevation. This maximum range is only of safety interest, not for combat firing.
|Single-shot hit-probability on Crouching Man (NATO E-type Silhouette) Target|
|Rifle||Chambering||Hit-probability (With no range estimation or aiming errors)|
|50 meters||100 meters||200 meters||300 meters||400 meters||500 meters||600 meters||700 meters||800 meters|
|M16A1 (1967)||5.56×45mm NATO M193||100%||100%||100%||100%||96%||87%||73%||56%||39%|
|M16A2 (1982)||5.56×45mm NATO SS109/M855||100%||100%||100%||100%||98%||90%||79%||63%||43%|
The 5.56×45mm cartridge had several advantages over the 7.62×51mm NATO round used in the M14 rifle. It enabled each soldier to carry more ammunition and was easier to control during automatic or burst fire. The 5.56×45mm NATO cartridge can also produce massive wounding effects when the bullet impacts at high speed and yaws ("tumbles") in tissue leading to fragmentation and rapid transfer of energy.
@ 10 meters
@ 100 meters
|3/4" pine boards
@ 100 meters
|Concrete building block
(one center rib)
|Steel helmet||1.9mm steel
@ 100 meters
|4mm steel |
+ layers of
|M16||5.56×45mm||M193||≈14 in (36 cm)
into smaller pieces)
|4 in (10 cm)
|one side to 200 m||both sides to 300 m
one side to 500 m
|2 layers||31 layers of Kevlar|
The original ammunition for the M16 was the 55-grain M193 cartridge. When fired from a 20" barrel at ranges of up to 100 meters, the thin-jacketed lead-cored round traveled fast enough (above 2900 ft/s) that the force of striking a human body would cause the round to yaw (or tumble) and fragment into about a dozen pieces of various sizes thus created wounds that were out of proportion to its caliber. These wounds were so devastating that many considered the M16 to be an inhumane weapon. As the 5.56mm round's velocity decreases, so does the number of fragments that it produces. The 5.56mm round does not normally fragment at distances beyond 200 meters or at velocities below 2500 ft/s, and its lethality becomes largely dependent on shot placement.
With the development of the M16A2, the new 62-grain M855 cartridge was adopted in 1983. The heavier bullet had more energy, and was made with a steel core to penetrate Soviet body armor. However, this caused less fragmentation on impact and reduced effects against targets without armor, both of which lessened kinetic energy transfer and wounding ability. Some soldiers and Marines coped with this through training, with requirements to shoot vital areas three times to guarantee killing the target.
However, there have been repeated and consistent reports of the M855's inability to wound effectively (i.e. fragment) when fired from the short barreled M4 carbine (even at close ranges). The M4's 14.5" barrel length reduces muzzle velocity to about 2900 ft/s. This reduced wounding ability is one reason that, despite the Army's transition to short-barrel M4's, the Marine Corps has decided to continue using the M16A4 with its 20″ barrel as the 5.56×45mm M855 is largely dependent upon high velocity in order to wound effectively.
In 2003, the U.S. Army contended that the lack of lethality of the 5.56×45mm was more a matter of perception than fact. With good shot placement to the head and chest, the target was usually defeated without issue. The majority of failures were the result of hitting the target in non-vital areas such as extremities. However, a minority of failures occurred in spite of multiple hits to the chest. In 2006, a study found that 20% of soldiers using the M4 Carbine wanted more lethality or stopping power. In June 2010, the U.S. Army announced it began shipping its new 5.56mm, lead-free, M855A1 Enhanced Performance Round to active combat zones. This upgrade is designed to maximize performance of the 5.56×45mm round, to extend range, improve accuracy, increase penetration and to consistently fragment in soft-tissue when fired from not only standard length M16s, but also the short-barreled M4 carbines. The U.S. Army has been impressed with the new M855A1 EPR round.
The M855A1 EPR may be green, and reports are still pretty thin, but it very well could be the ammunition the Army was asking for all along.[tone] It is more effective all around, with improved penetration through Kevlar, mild steel, concrete, and vehicle components like doors and auto glass and even helicopters bodies, to name a few, and better accuracy, higher velocities, less wind sensitivity and more precision complementing its superior terminal results. that they developed a 7.62 NATO M80A1 EPR variant.
The M16's magazine was meant to be a lightweight, disposable item. As such, it is made of pressed/stamped aluminum and was not designed to be durable. The M16 originally used a 20-round magazine which was later replaced by a bent 30-round design. As a result, the magazine follower tends to rock or tilt, causing malfunctions. Many non-U.S. and commercial magazines have been developed to effectively mitigate these shortcomings (e.g., H&K's all-stainless-steel magazine, Magpul's polymer P-MAG, etc.).
Production of the 30-round magazine started late 1967 but did not fully replace the 20-round magazine until the mid-1970s. Standard USGI aluminum 30-round M16 magazines weigh 0.24 lb (0.11 kg) empty and are 7.1 inches (18 cm) long. The newer plastic magazines are about a half-inch longer. The newer steel magazines are about 0.5-inch longer and four ounces heavier. The M16's magazine has become the unofficial NATO STANAG magazine and is currently used by many Western Nations, in numerous weapon systems.
In 2009, the U.S. Military began fielding an "improved magazine" identified by a tan-colored follower. "The new follower incorporates an extended rear leg and modified bullet protrusion for improved round stacking and orientation. The self-leveling/anti-tilt follower minimizes jamming while a wider spring coil profile creates even force distribution. The performance gains have not added weight or cost to the magazines."
In July 2016, the U.S. Army introduced another improvement, the new Enhanced Performance Magazine, which it says will result in a 300% increase in reliability in the M4 Carbine. Developed by the United States Army Armament Research, Development and Engineering Center and the Army Research Laboratory in 2013, it is tan colored with blue follower to distinguish it from earlier, incompatible magazines.
Most M16 rifles have a barrel threaded in 1⁄2-28" threads to incorporate the use of a muzzle device such as a flash suppressor or sound suppressor. The initial flash suppressor design had three tines or prongs and was designed to preserve the shooter's night vision by disrupting the flash. Unfortunately it was prone to breakage and getting entangled in vegetation. The design was later changed to close the end to avoid this and became known as the "A1" or "bird cage" flash suppressor on the M16A1. Eventually on the M16A2 version of the rifle, the bottom port was closed to reduce muzzle climb and prevent dust from rising when the rifle was fired in the prone position. For these reasons, the U.S. military declared the A2 flash suppressor as a compensator or a muzzle brake; but it is more commonly known as the "GI" or "A2" flash suppressor.
The M16's Vortex Flash Hider weighs 3 ounces, is 2.25 inches long, and does not require a lock washer to attach to barrel. It was developed in 1984, and is one of the earliest privately designed muzzle devices. The U.S. military uses the Vortex Flash Hider on M4 carbines and M16 rifles. A version of the Vortex has been adopted by the Canadian Military for the Colt Canada C8 CQB rifle. Other flash suppressors developed for the M16 include the Phantom Flash Suppressor by Yankee Hill Machine (YHM) and the KX-3 by Noveske Rifleworks.
The threaded barrel allows sound suppressors with the same thread pattern to be installed directly to the barrel; however this can result in complications such as being unable to remove the suppressor from the barrel due to repeated firing on full auto or three-round burst. A number of suppressor manufacturers have designed "direct-connect" sound suppressors which can be installed over an existing M16's flash suppressor as opposed to using the barrel's threads.
Grenade launchers and shotguns
All current M16 type rifles can mount under-barrel 40 mm grenade-launchers, such as the M203 and M320. Both use the same 40 mm grenades as the older, stand-alone M79 grenade launcher. The M16 can also mount under-barrel 12 gauge shotguns such as KAC Masterkey or the M26 Modular Accessory Shotgun System.
Riot Control Launcher
The M234 Riot Control Launcher is an M16-series rifle attachment firing an M755 blank round. The M234 mounts on the muzzle, bayonet lug and front sight post of the M16. It fires either the M734 64 mm Kinetic Riot Control or the M742 64 mm CSI Riot Control Ring Airfoil Projectiles. The latter produces a 4 to 5-foot tear gas cloud on impact. The main advantage to using Ring Airfoil Projectiles is that their design does not allow them be thrown back by rioters with any real effect. The M234 is no longer used by U.S. forces. It has been replaced by the M203 40 mm grenade launcher and nonlethal ammunition.
The M16 is 44.25 inches (1124 mm) long with an M7 bayonet attached. The M7 bayonet is based on earlier designs such as the M4, M5, & M6 bayonets, all of which are direct descendants of the M3 Fighting Knife and have spear-point blade with a half sharpened secondary edge. The newer M9 bayonet has a clip-point blade with saw teeth along the spine, and can be used as a multi-purpose knife and wire-cutter when combined with its scabbard. The current USMC OKC-3S bayonet bears a resemblance to the Marines' iconic Ka-Bar fighting knife with serrations near the handle.
For use as an ad-hoc automatic rifle, the M16 and M16A1 could be equipped with the XM3 bipod, later standardized as the Bipod, M3 (1966) and Rifle Bipod M3 (1983). Weighing only 0.6 lb, the simple and non-adjustable bipod clamped unto the barrel of the rifle to allow for supported fire.
The M3 bipod continues to be referenced in at least one official manual as late as 1985, where it is stated one of the most stable firing positions is "the prone biped [sic] supported for automatic fire."
In March 1970, the U.S. recommended that all NATO forces adopt the 5.56×45mm cartridge. This shift represented a change in the philosophy of the military's long-held position about caliber size. By the mid 1970s, other armies were looking at M16-style weapons. A NATO standardization effort soon started and tests of various rounds were carried out starting in 1977. The U.S. offered the 5.56×45mm M193 round, but there were concerns about its penetration in the face of the wider introduction of body armor. In the end the Belgian 5.56×45mm SS109 round was chosen (STANAG 4172) in October 1980. The SS109 round was based on the U.S. cartridge but included a new stronger, heavier, 62 grain bullet design, with better long range performance and improved penetration (specifically, to consistently penetrate the side of a steel helmet at 600 meters). Due to its design and lower muzzle velocity (about 3110 ft/s) the Belgian SS109 round is considered more humane because it is less likely to fragment than the U.S. M193 round. The NATO 5.56×45mm standard ammunition produced for U.S. forces is designated M855.
In October 1980, shortly after NATO accepted the 5.56×45mm NATO rifle cartridge. Draft Standardization Agreement 4179 (STANAG 4179) was proposed to allow NATO members to easily share rifle ammunition and magazines down to the individual soldier level. The magazine chosen to become the STANAG magazine was originally designed for the U.S. M16 rifle. Many NATO member nations, but not all, subsequently developed or purchased rifles with the ability to accept this type of magazine. However, the standard was never ratified and remains a 'Draft STANAG'.
All current M16 type rifles are designed to fire STANAG 22 mm rifle grenades from their integral flash hiders without the use of an adapter. These 22 mm grenade types range from anti-tank rounds to simple finned tubes with a fragmentation hand grenade attached to the end. They come in the "standard" type which are propelled by a blank cartridge inserted into the chamber of the rifle. They also come in the "bullet trap" and "shoot through" types, as their names imply, they use live ammunition. The U.S. military does not generally use rifle grenades; however, they are used by other nations.
The NATO Accessory Rail STANAG 4694, or Picatinny rail STANAG 2324, or a "Tactical Rail" is a bracket used on M16 type rifles to provide a standardized mounting platform. The rail comprises a series of ridges with a T-shaped cross-section interspersed with flat "spacing slots". Scopes are mounted either by sliding them on from one end or the other; by means of a "rail-grabber" which is clamped to the rail with bolts, thumbscrews or levers; or onto the slots between the raised sections. The rail was originally for scopes. However, once established, the use of the system was expanded to other accessories, such as tactical lights, laser aiming modules, night vision devices, reflex sights, foregrips, bipods, and bayonets.
Currently, the M16 is in use by 15 NATO countries and more than 80 countries worldwide.
The weapon that eventually became the M16 series was basically a scaled down AR-10 with an ambidextrous charging handle located within the carrying handle, a narrower front sight "A" frame, and no flash suppressor.
Colt ArmaLite AR-15 (Models 601 & 602)
Colt's first two models produced after the acquisition of the rifle from ArmaLite were the 601 and 602, and these rifles were in many ways clones of the original ArmaLite rifle (in fact, these rifles were often found stamped Colt ArmaLite AR-15, Property of the U.S. Government caliber .223, with no reference to them being M16s). The 601 and 602 are easily identified by their flat lower receivers without raised surfaces around the magazine well and occasionally green or brown furniture. The 601 was adopted first of any of the rifles by the USAF, and was quickly supplemented with the XM16 (Colt Model 602) and later the M16 (Colt Model 604) as improvements were made. There was also a limited purchase of 602s, and a number of both of these rifles found their way to a number of Special Operations units then operating in South East Asia, most notably the U.S. Navy SEALs. The only major difference between the 601 and 602 is the switch from the original 1:14-inch rifling twist to the more common 1:12-inch twist. These weapons were equipped with a triangular charging handle and a bolt hold open device that lacked a raised lower engagement surface. The bolt hold open device had a slanted and serrated surface that had to be engaged with a bare thumb, index finger, or thumbnail because of the lack of this surface. The U.S. Air Force continued to use the ArmaLite AR-15 marked rifles in various configurations into the 1990s.
This was the first M16 variant adopted operationally, originally by the U.S. Air Force. It was equipped with triangular handguards, butt stocks without a compartment for the storage of a cleaning kit, a three-pronged flash suppressor, full auto, and no forward assist. Bolt carriers were originally chrome plated and slick-sided, lacking forward assist notches. Later, the chrome plated carriers were dropped in favor of Army issued notched and parkerized carriers though the interior portion of the bolt carrier is still chrome-lined. The Air Force continued to operate these weapons until around 2001, at which time the Air Force converted all of its M16s to the M16A2 configuration.
XM16E1 and M16A1 (Colt Model 603)
The U.S. Army XM16E1 was essentially the same weapon as the M16 with the addition of a forward assist and corresponding notches in the bolt carrier. The M16A1 was the finalized production model in 1967 and was produced until 1982.
To address issues raised by the XM16E1's testing cycle, a closed, bird-cage flash suppressor replaced the XM16E1's three-pronged flash suppressor which caught on twigs and leaves. Various other changes were made after numerous problems in the field. Cleaning kits were developed and issued while barrels with chrome-plated chambers and later fully lined bores were introduced.
With these and other changes, the malfunction rate slowly declined and new soldiers were generally unfamiliar with early problems. A rib was built into the side of the receiver on the XM16E1 to help prevent accidentally pressing the magazine release button while closing the ejection port cover. This rib was later extended on production M16A1s to help in preventing the magazine release from inadvertently being pressed. The hole in the bolt that accepts the cam pin was crimped inward on one side, in such a way that the cam pin may not be inserted with the bolt installed backwards, which would cause failures to eject until corrected. The M16A1 saw limited use in training capacities until the early 2000s, but is no longer in active service with the U.S., although is still standard issue in many world armies.
The development of the M16A2 rifle was originally requested by the United States Marine Corps as a result of combat experience in Vietnam with the XM16E1 and M16A1. It was officially adopted by the Department of Defense as the "US Rifle, 5.56mm, M16A2" in 1982. The Marines were the first branch of the U.S. Armed Forces to adopt it, in the early/mid-1980s, with the United States Army following suit in the late 1980s.
Modifications to the M16A2 were extensive. In addition to the new rifling, the barrel was made with a greater thickness in front of the front sight post, to resist bending in the field and to allow a longer period of sustained fire without overheating. The rest of the barrel was maintained at the original thickness to enable the M203 grenade launcher to be attached. A new adjustable rear sight was added, allowing the rear sight to be dialed in for specific range settings between 300 and 800 meters to take full advantage of the ballistic characteristics of the new SS109 rounds and to allow windage adjustments without the need of a tool or cartridge. The weapon's reliability allowed it to be widely used around the Marine Corps' special operations divisions as well. The flash suppressor was again modified, this time to be closed on the bottom so it would not kick up dirt or snow when being fired from the prone position, and acting as a recoil compensator.
The front grip was modified from the original triangular shape to a round one, which better fit smaller hands and could be fitted to older models of the M16. The new handguards were also symmetrical so armories need not separate left- and right-hand spares. The handguard retention ring was tapered to make it easier to install and uninstall the handguards. A notch for the middle finger was added to the pistol grip, as well as more texture to enhance the grip. The buttstock was lengthened by 5⁄8 in (15.9 mm). The new buttstock became ten times stronger than the original due to advances in polymer technology since the early 1960s. Original M16 stocks were made from fiberglass-impregnated resin; the newer stocks were engineered from DuPont Zytel glass-filled thermoset polymers. The new stock included a fully textured polymer buttplate for better grip on the shoulder, and retained a panel for accessing a small compartment inside the stock, often used for storing a basic cleaning kit. The heavier bullet reduces muzzle velocity from 3,200 feet per second (980 m/s), to about 3,050 feet per second (930 m/s).
The A2 uses a faster 1:7 twist rifling to allow use of a trajectory-matched tracer round. A spent case deflector was incorporated into the upper receiver immediately behind the ejection port to prevent cases from striking left-handed users. The action was also modified, replacing the fully automatic setting with a three-round burst setting. When using a fully automatic weapon, inexperienced troops often hold down the trigger and "spray" when under fire. The U.S. Army concluded that three-shot groups provide an optimum combination of ammunition conservation, accuracy, and firepower. The USMC has retired the M16A2 in favor of the newer M16A4; a few M16A2s remain in service with the U.S. Army Reserve and National Guard, Air Force, Navy and Coast Guard.
The M16A3 is a modified version of the M16A2 adopted in small numbers by the U.S. Navy SEAL, Seabee, and Security units. It features the M16A1 trigger group providing "safe", "semi-automatic" and "fully automatic" modes instead of the A2's "safe", "semi-automatic", and "burst" modes. Otherwise it is externally identical to the M16A2.
The M16A4 is the fourth generation of the M16 series. It is equipped with a removable carrying handle and a full length quad Picatinny rail for mounting optics and other ancillary devices. The FN M16A4, using safe/semi/burst selective fire, became standard issue for the U.S. Marine Corps.
Military issue rifles are also equipped with a Knight's Armament Company M5 RAS hand guard, allowing vertical grips, lasers, tactical lights, and other accessories to be attached, coining the designation M16A4 MWS (or Modular Weapon System) in U.S. Army field manuals.
Colt also produces M16A4 models for international purchases:
- R0901 / NSN 1005-01-383-2872 (Safe/Semi/Auto)
- R0905 (Safe/Semi/Burst)
A study of significant changes to Marine M16A4 rifles released in February 2015 outlined several new features that could be added from inexpensive and available components. Those features included: a muzzle compensator in place of the flash suppressor to manage recoil and allow for faster follow-on shots, though at the cost of noise and flash signature and potential overpressure in close quarters; a heavier and/or free-floating barrel to increase accuracy from 4.5 MOA (Minute(s) Of Angle) to potentially 2 MOA; changing the reticle on the Rifle Combat Optic from chevron-shaped to the semi-circle with a dot at the center used in the M27 IAR's Squad Day Optic so as not to obscure the target at long distance; using a trigger group with a more consistent pull force, even a reconsideration of the burst capability; and the addition of ambidextrous charging handles and bolt catch releases for easier use with left-handed shooters.
In 2014, Marine units were provided with a limited number of adjustable stocks in place of the traditional fixed stock for their M16A4s to issue to smaller Marines who would have trouble comfortably reaching the trigger when wearing body armor. The adjustable stocks were added as a standard authorized accessory, meaning units can use operations and maintenance funds to purchase more if needed.
The Marine Corps had long maintained the full-length M16 as their standard infantry rifle, but in October 2015 the switch to the M4 carbine was approved as the standard-issue weapon, giving Marine infantrymen a smaller and more compact weapon. Enough M4s are already in the inventory to re-equip all necessary units by September 2016, and M16A4s will be moved to support and non-infantry Marines.
In the 1970s, Singapore was looking for an assault rifle for the Singapore Armed Forces and chose both the M16 and ArmaLite AR-15. Since importing M16s from the US would be difficult, they made their own copies of the M16, designated M16S1; "S" stood for Singapore. It was replaced by the SAR 21, which was introduced during 1999 and 2000, but is still kept for reserve forces.
Summary of differences
|Colt model no.||Military designation||20" Barrel w/ bayonet lug||Handguard type||Buttstock type||Pistol grip type||Lower receiver type||Upper receiver type||Rear sight type||Front sight type||Muzzle device||Forward assist?||Case deflector?||Trigger pack|
|601||AR-15||A1 profile (1:14 twist)||Green or brown full-length triangular||Green or brown fixed A1||A1||A1||A1||A1||A1||Duckbill flash suppressor||No||No||Safe/Semi/Auto|
|602||XM16||A1 profile (1:12 twist)||Full-length triangular||Fixed A1||A1||A1||A1||A1||A1||Duckbill or three-prong flash suppressor||No||No||Safe/Semi/Auto|
|603||XM16E1||A1 profile (1:12 twist)||Full-length triangular||Fixed A1||A1||A1||A1||A1||A1||Three-prong or M16A1 birdcage flash suppressor||Yes||No||Safe/Semi/Auto|
|603||M16A1||A1 profile (1:12 twist)||Full-length triangular||Fixed A1||A1||A1||A1||A1||A1||Three-prong or birdcage flash suppressor||Yes||No||Safe/Semi/Auto|
|604||M16||A1 profile (1:12 twist)||Full-length triangular||Fixed A1||A1||A1||A1||A1||A1||Three-prong or M16A1-style birdcage flash suppressor||No||No||Safe/Semi/Auto|
|645||M16A1E1/PIP||A2 profile (1:7 twist)||Full-length ribbed||Fixed A2||A1||A1 or A2||A1 or A2||A1 or A2||A2||M16A1 or M16A2-style birdcage flash suppressor||Yes||Yes or No||Safe/Semi/Auto or Safe/Semi/Burst|
|645||M16A2||A2 profile (1:7 twist)||Full-length ribbed||Fixed A2||A2||A2||A2||A2||A2||M16A2-style birdcage flash suppressor||Yes||Yes||Safe/Semi/Burst
|645E||M16A2E1||A2 profile (1:7 twist)||Full-length ribbed||Fixed A2||A2||A2||Flattop with Colt Rail||Flip-up||Folding||M16A2-style birdcage flash suppressor||Yes||Yes||Safe/Semi/Burst
or Safe/Semi/ Burst/Auto
|N/A||M16A2E2||A2 profile (1:7 twist)||Full-length semi-beavertail w/ HEL guide||Retractable ACR||ACR||A2||Flattop with Colt rail||None||A2||ACR muzzle brake||Yes||Yes||Safe/Semi/Burst
|646||M16A3 (M16A2E3)||A2 profile (1:7 twist)||Full-length ribbed||Fixed A2||A2||A2||A2||A2||A2||M16A2-style birdcage flash suppressor||Yes||Yes||Safe/Semi/Auto|
|655||M16A1 Special High Profile||HBAR profile
|Full-length triangular||Fixed A1||A1||A1||A1||A1||A1||M16A1-style birdcage flash suppressor||Yes||No||Safe/Semi/Auto|
|656||M16A1 Special Low Profile||HBAR profile
|Full-length triangular||Fixed A1||A1||A1||A1 with modified Weaver base||Low Profile A1||Hooded A1||M16A1-style birdcage flash suppressor||Yes||No||Safe/Semi/Auto|
|945||M16A4 (M16A2E4)||A2 profile (1:7 twist)||Full-length ribbed or KAC M5 RAS||Fixed A2||A2||A2||Flattop with MIL-STD-1913 rail||None||A4||M16A2-style birdcage flash suppressor||Yes||Yes||Safe/Semi/Burst|
|Colt model no.||Military designation||20" Barrel w/ bayonet lug||Handguard type||Buttstock type||Pistol grip type||Lower receiver type||Upper receiver type||Rear sight type||Front sight type||Muzzle device||Forward assist?||Case deflector?||Trigger pack|
Colt Commando (AKA: XM177 & GAU-5)
In Vietnam, some soldiers were issued a carbine version of the M16 named XM177. The XM177 had a shorter 10 in (254 mm) barrel and a telescoping stock, which made it substantially more compact. It also possessed a combination flash hider/sound moderator to reduce problems with muzzle flash and loud report. The Air Force's GAU-5/A (XM177) and the Army's XM177E1 variants differed over the latter's inclusion of a forward assist, although some GAU-5s do have the forward assist. The final Air Force GAU-5/A and Army XM177E2 had an 11.5 in (292 mm) barrel with a longer flash/sound suppressor. The lengthening of the barrel was to support the attachment of Colt's own XM148 40 mm grenade launcher. These versions were also known as the Colt Commando model commonly referenced and marketed as the CAR-15. The variants were issued in limited numbers to special forces, helicopter crews, Air Force pilots, Air Force Security Police Military Working Dog (MWD) handlers, officers, radio operators, artillerymen, and troops other than front line riflemen. Some USAF GAU-5A/As were later equipped with even longer 14.5-inch (370 mm) 1/12 rifled barrels as the two shorter versions were worn out. The 14.5-inch (370 mm) barrel allowed the use of MILES gear and for bayonets to be used with the sub-machine guns (as the Air Force described them). By 1989, the Air Force started to replace the earlier barrels with 1/7 rifled models for use with the M855-round. The weapons were given the redesignation of GUU-5/P.
The M4 carbine was developed from various outgrowths of these designs, including a number of 14.5-inch (368 mm)-barreled A1 style carbines. The XM4 (Colt Model 720) started its trials in 1984, with a barrel of 14.5 inches (370 mm). The weapon became the M4 in 1991. Officially adopted as a replacement for the M3 "Grease Gun" (and the Beretta M9 and M16A2 for select troops) in 1994, it was used with great success in the Balkans and in more recent conflicts, including the Afghanistan and Iraq theaters. The M4 carbine has a three-round burst firing mode, while the M4A1 carbine has a fully automatic firing mode. Both have a Picatinny rail on the upper receiver, allowing the carry handle/rear sight assembly to be replaced with other sighting devices.
Colt also returned to the original "Commando" idea, with its Model 733, essentially a modernized XM177E2 with many of the features introduced on the M16A2.
Diemaco C7 and C8
The Diemaco C7 and C8 are updated variants of the M16 developed and used by the Canadian Forces and are now manufactured by Colt Canada. The C7 is a further development of the experimental M16A1E1. Like earlier M16s, it can be fired in either semi-automatic or automatic mode, instead of the burst function selected for the M16A2. The C7 also features the structural strengthening, improved handguards, and longer stock developed for the M16A2. Diemaco changed the trapdoor in the buttstock to make it easier to access and a spacer of 0.5 inches (13 mm) is available to adjust stock length to user preference. The most easily noticeable external difference between American M16A2s and Diemaco C7s is the retention of the A1 style rear sights. Not easily apparent is Diemaco's use of hammer-forged barrels. The Canadians originally desired to use a heavy barrel profile instead.
The C7 has been developed to the C7A1, with a Weaver rail on the upper receiver for a C79 optical sight, and to the C7A2, with different furniture and internal improvements. The Diemaco produced Weaver rail on the original C7A1 variants does not meet the M1913 "Picatinny" standard, leading to some problems with mounting commercial sights. This is easily remedied with minor modification to the upper receiver or the sight itself. Since Diemaco's acquisition by Colt to form Colt Canada, all Canadian produced flattop upper receivers are machined to the M1913 standard.
The C8 is the carbine version of the C7. The C7 and C8 are also used by Hærens Jegerkommando, Marinejegerkommandoen and FSK (Norway), Military of Denmark (all branches), the Royal Netherlands Army and Netherlands Marine Corps as its main infantry weapon. Following trials, variants became the weapon of choice of the British SAS.
Heckler & Koch HK416
The Heckler & Koch HK416 is an assault rifle designed and manufactured by Heckler & Koch. It is based on the M16, and was originally conceived as an improvement based on the Colt M4 carbine family issued to the U.S. military, with the notable inclusion of an HK-proprietary short-stroke gas piston system derived from the Heckler & Koch G36. The HK416 was used by U.S. Navy SEALs to kill Osama bin Laden.
Mk 4 Mod 0
The Mk 4 Mod 0 was a variant of the M16A1 produced for the U.S. Navy SEALs during the Vietnam War and adopted in April 1970. It differed from the basic M16A1 primarily in being optimized for maritime operations and coming equipped with a sound suppressor. Most of the operating parts of the rifle were coated in Kal-Guard, a hole of 0.25 inches (6.4 mm) was drilled through the stock and buffer tube for drainage, and an O-ring was added to the end of the buffer assembly. The weapon could reportedly be carried to the depth of 200 feet (60 m) in water without damage. The initial Mk 2 Mod 0 Blast Suppressor was based on the U.S. Army's Human Engineering Lab's (HEL) M4 noise suppressor. The HEL M4 vented gas directly from the action, requiring a modified bolt carrier. A gas deflector was added to the charging handle to prevent gas from contacting the user. Thus, the HEL M4 suppressor was permanently mounted though it allowed normal semi-automatic and automatic operation. If the HEL M4 suppressor were removed, the weapon would have to be manually loaded after each single shot. On the other hand, the Mk 2 Mod 0 blast suppressor was considered an integral part of the Mk 4 Mod 0 rifle, but it would function normally if the suppressor were removed. The Mk 2 Mod 0 blast suppressor also drained water much more quickly and did not require any modification to the bolt carrier or to the charging handle. In the late 1970s, the Mk 2 Mod 0 blast suppressor was replaced by the Mk 2 blast suppressor made by Knight's Armament Company (KAC). The KAC suppressor can be fully submerged and water will drain out in less than eight seconds. It will operate without degradation even if the rifle is fired at the maximum rate of fire. The U.S. Army replaced the HEL M4 with the much simpler Studies in Operational Negation of Insurgency and Counter-Subversion (SIONICS) MAW-A1 noise and flash suppressor.
Developed to increase the effective range of soldiers in the designated marksman role, the U.S. Navy developed the Mark 12 Special Purpose Rifle (SPR). Configurations in service vary, but the core of the Mark 12 SPR is an 18" heavy barrel with muzzle brake and free float tube. This tube relieves pressure on the barrel caused by standard handguards and greatly increases the potential accuracy of the system. Also common are higher magnification optics ranging from the 6× power Trijicon ACOG to the Leupold Mark 4 Tactical rifle scopes. Firing Mark 262 Mod 0 ammunition with a 77gr Open tip Match bullet, the system has an official effective range of 600+ meters. However published reports of confirmed kills beyond 800 m from Iraq and Afghanistan are not uncommon.
M231 Firing Port Weapon (FPW)
The M231 Firing Port Weapon (FPW) is an adapted version of the M16 assault rifle for firing from ports on the M2 Bradley. The infantry's normal M16s are too long for use in a "buttoned up" fighting vehicle, so the FPW was developed to provide a suitable weapon for this role.
Colt Model 655 and 656 "Sniper" variants
With the expanding Vietnam War, Colt developed two rifles of the M16 pattern for evaluation as possible light sniper or designated marksman rifles. The Colt Model 655 M16A1 Special High Profile was essentially a standard A1 rifle with a heavier barrel and a scope bracket that attached to the rifle's carry handle. The Colt Model 656 M16A1 Special Low Profile had a special upper receiver with no carrying handle. Instead, it had a low-profile iron sight adjustable for windage and a Weaver base for mounting a scope, a precursor to the Colt and Picatinny rails. It also had a hooded front iron sight in addition to the heavy barrel. Both rifles came standard with either a Leatherwood/Realist scope 3–9× Adjustable Ranging Telescope. Some of them were fitted with a Sionics noise and flash suppressor. Neither of these rifles were ever standardized.
- The Chinese Norinco CQ is an unlicensed derivative of the M16A1 made specifically for export, with the most obvious external differences being in its handguard and revolver-style pistol grip.
- The ARMADA rifle (a copy of the Norinco CQ) and TRAILBLAZER carbine (a copy of the Norinco CQ Type A) are manufactured by S.A.M. – Shooter's Arms Manufacturing, a.k.a. Shooter's Arms Guns & Ammo Corporation, headquartered in Metro Cebu, Republic of the Philippines.
- The S-5.56 rifle, a clone of the Type CQ, is manufactured by the Defense Industries Organization of Iran. The rifle itself is offered in two variants: the S-5.56 A1 with a 19.9-inch barrel and 1:12 pitch rifling (1 turn in 305 mm), optimized for the use of the M193 Ball cartridge; and the S-5.56 A3 with a 20-inch barrel and a 1:7 pitch rifling (1 turn in 177, 8 mm), optimized for the use of the SS109 cartridge.
- The KH-2002 is an Iranian bullpup conversion of the locally produced S-5.56 rifle. Iran intends to replace the standard issue weapon of its armed forces with this rifle.
- The Terab rifle is a copy of the DIO S-5.56 manufactured by the Military Industry Corporation of Sudan.
- The M16S1 is the M16A1 rifle made under license by ST Kinetics in Singapore. It was the standard issue weapon of the Singapore Armed Forces. It is being replaced by the newer SAR 21 in most branches. It is, in the meantime, the standard issue weapon in the reserve forces.
- The MSSR rifle is a sniper rifle developed by the Philippine Marine Corps Scout Snipers that serves as their primary sniper weapon system.
- The Special Operations Assault Rifle (SOAR) assault carbine was developed by Ferfrans based on the M16 rifle. It is used by the Special Action Force of the Philippine National Police.
- Taiwan uses piston-driven M16-based weapons as their standard rifle. These include the T65, T86 and T91 assault rifles.
- Ukraine has announced plans in January 2017 for Ukroboronservis and Aeroscraft to produce the M16 WAC47, an accurized M4 variation that uses standard 7.62×39mm AK-47 magazines.
As of November 2019, no weapon manufactured as described in the above lines, has been produced.
- New Zealand has adopted the Lewis Machine and Tool Company's upgraded version of the M16 system to replace the Steyr AUG. This CQB16 rifle will be fielded in 2017 and is named MARS-L (Modular Ambidextrous Rifle System-Light).
Production and users
The M16 is the most commonly manufactured 5.56×45mm rifle in the world. Currently, the M16 is in use by 15 NATO countries and more than 80 countries worldwide. Together, numerous companies in the United States, Canada, and China have produced more than 8,000,000 rifles of all variants. Approximately 90% are still in operation. The M16 replaced both the M14 rifle and M2 carbine as standard infantry rifle of the U.S. armed forces. Although, the M14 continues to see limited service, mostly in sniper, designated marksman, and ceremonial roles.
- Afghanistan: Standard issue rifle of the Afghan National Army. Colt Canada C7 variants also saw limited service.
- Argentina: Special Forces used the M16A1 in the Falklands War and they currently use the M16A2 (by all Armed Forces).
- Bangladesh: M16A4, used by the military, special forces and counter terrorism units.
- Bosnia and Herzegovina: M16A1
- Brazil: M16A2s used by Brazilian Marine Corps
- Brunei M16A2 is used by the Royal Brunei Armed Forces as their main service rifle.
- Burundi: Burundian rebels
- Cambodia M16A1
- Canada: C7 and C8 variants made by Colt Canada are used by the Canadian Forces.
- Central African Republic
- Chile M16A1 used by Chilean Marine Corps.
- Costa Rica
- Denmark: C7 and C8 variants made by Colt Canada are used by all branches of the Danish Defence.
- Dominican Republic
- East Timor M16A2
- El Salvador M16A1/A2/A4
- Estonia Ex-U.S. M16A1s
- France: used by counter-terrorism and special operations forces
- Ghana M16A2
- Greece M16A2/A3/A4/M4 is used by the Special Forces of the Hellenic Army ISAF Forces in Afghanistan and the Hellenic Navy.
- Guatemala M16A1/M16A2.
- Honduras M16A1
- Iraq: Used by Iraqi Army.
- Israel Being replaced by IMI Tavor.
- Ivory Coast
- Japan: M16A1 is used by Western Army Infantry Regiment along with Howa Type 89 rifles.
- Jordan M16A1/A2
- Nicaragua: Used by the National Police of Nicaragua and army.
- North Korea: M16A1 (probably unlicensed copies) used by KPA special forces. Used during the Gangneung incident in 1996.
- South Korea: During the Vietnam War, the U.S. provided 27,000 M16 rifles to the Republic of Korea Armed Forces in Vietnam. Also, 600,000 M16A1s (Colt Model 603K) were manufactured under license by Daewoo Precision Industries with deliveries from 1974 to 1985. KATUSA (Korean Augmentation to the U.S. Army) soldiers who serve in the U.S. Army use the M16A2.
- Kuwait M16A1/A2.
- Lebanon M16A1/A2/A4.
- Liberia M16A2
- Lithuania: Lithuanian Armed Forces
- Malaysia Malaysian Armed Forces, Royal Malaysia Police, Malaysian Maritime Enforcement Agency and RELA Corps.
- Mauritius[better source needed]
- Mexico: M16A2 is used by the Mexican Marines in the Mexican Drug War.
- Monaco: Compagnie des Carabiniers du Prince
- Morocco M16A1/M16A2/M16A3/M16A4
- Nepal M16A2 and M16A4; captured M16A2 were also used by Maoist rebels of the People's Liberation Army, Nepal during the Nepalese Civil War.
- Netherlands: C7 and C8 variants are used by the Military of the Netherlands and LSW is used by Netherlands Marine Corps.
- Pakistan M16A1
- Palestinian Authority: Used by Palestinian Security Forces and various local militant forces.
- Panama M16A1.
- Papua New Guinea M16A2.
- Peru M16A2.
- Philippines: Manufactured under license by Elisco Tool and Manufacturing. M16A1s and M653Ps in use. Supplemented in Special Forces by the M4 carbine.
- Poland:The Polish Military Unit GROM used civilian M4 clones, or Bushmaster XM15E2S M4A3 and KAC SR-16 Carbine, as the basic weapon. Since 2008, they have been replaced by the HK416 rifle.
- Qatar M16A1.
- Senegal: M16A1 and M16A2
- Sierra Leone: 1,000+ M16A1s in use
- Singapore: Local variant of the M16A1 (M16S1) manufactured under license by ST Kinetics.
- South Africa: Used by Special Forces. Likely received from Moroccan stocks.
- Sri Lanka
- Sweden A small number of M16A2s are used by the Swedish Armed Forces for familiarization training, as well as a similar number of AKMs, but they are not issued to combat units. The Ak 4 and Ak 5 rifles are used by Swedish Army.
- Taiwan Type 65, 85 and 91 Taiwanese Assault rifles modeled after the M16A2.
- Thailand M16A1/A2/A4.
- Tunisia M16A2/A4.
- Turkey M16A1/A2/A4.
- United Arab Emirates
- United Kingdom: One of first military customers as UK purchased first AR-15s to be used in jungle warfare in Indonesia-Malaysia confrontation. The Colt Canada C8 (L119A1/L119A2) variant is used by Royal Military Police Close Protection Units, the Pathfinder Group, United Kingdom Special Forces and 43 Commando Fleet Protection Group Royal Marines.
- United States
- Vietnam: Obtained from South Vietnam following Vietnam War Over 946,000 M16s were captured in 1975 alone.
- Australia M16A1 introduced during the Vietnam War and replaced by the F88 Austeyr in 1989.
- Croatia M16A2 smuggled into country in small quantities, used in Croatian War of Independence and Croat-Bosniak War
- New Zealand M16; replaced in 1988 by Steyr AUG, which was being replaced with a non-Colt M16 variant in 2016.
- Laos: Received from the US government during the Vietnam War and Laotian Civil War.
- Rhodesia: M16A1
- South Vietnam: 6,000 M16 and 938,000 M16A1, 1966–1975
- Provisional IRA - received a number of M16s during The Troubles in Northern Ireland.
- Adaptive Combat Rifle
- List of Colt AR-15 and M16 rifle variants
- Colt 9 mm SMG
- Comparison of the AK-47 and M16
- Daewoo K2, Republic of Korea Armed Forces (South Korea) assault rifle
- List of individual weapons of the U.S. armed forces
- M203 40 mm grenade launcher
- MSBS Radon
- Norinco CQ, M16 clone developed by China
- Robinson Arms XCR
- Rubber duck (military)
- T65 assault rifle, AR-15 variant developed by ROC Army
- Winchester LMR
- Table of handgun and rifle cartridges
- List of assault rifles
- Rottman, Gordon L. (20 December 2011). The M16. Weapon 14. Osprey Publishing. ISBN 978-1-84908-691-2.
- "Report of the M16 Rifle Review Panel" (PDF). Defense Technical Information Center (DTIC). Department of the Army. 1 June 1968. Archived from the original (PDF) on 24 September 2015.
- Conboy, Kenneth; Bowra, Ken (15 June 1989). The War in Cambodia 1970–75. Men-at-Arms 209. Osprey Publishing. pp. 18, 41–42. ISBN 9780850458510.
- Schroeder, Matt (2013). "Captured and Counted: Illicit Weapons in Mexico and the Philippines" (PDF). Small Arms Survey 2013: Everyday Dangers. Cambridge University Press. p. 303. ISBN 978-1-107-04196-7. Archived from the original on 21 March 2019. Retrieved 5 June 2019.
- Reyeg, Fernando M.; Marsh, Ned B. (December 2011). The Filipino Way of War: Irregular Warfare through the Centuries (Master Thesis). Naval Postgraduate School. p. 114. hdl:10945/10681.
- Sicard, Jacques (November 1982). "Les armes de Kolwezi". La Gazette des armes (in French). No. 111. pp. 25–30. Archived from the original on 19 October 2018. Retrieved 18 October 2018.
- Huband, Mark (17 June 2013). The Liberian Civil War. Routledge. p. 62. ISBN 978-1-135-25221-2 – via Google Books.
- Wille, Christina (May 2005). "Children Associated with Fighting Forces and Small Arms in the Mano River Union" (PDF). In Florquin, Nicolas; Berman, Eric G. (eds.). Armed and Aimless: Armed Groups, Guns, and Human Security in the ECOWAS Region. Small Arms Survey. p. 197. ISBN 2-8288-0063-6. Archived from the original on 31 January 2019. Retrieved 30 January 2019.
- Small Arms Survey (2005). "The Central African Republic: A Case Study of Small Arms and Conflict" (PDF). Small Arms Survey 2005: Weapons at War. Oxford University Press. p. 318. ISBN 978-0-19-928085-8. Archived from the original on 30 August 2018. Retrieved 29 August 2018.
- Berman, Eric G.; Racovita, Mihaela (July 2015). Under Attack and Above Scrutiny? Arms and Ammunition Diversion from Peacekeepers in Sudan and South Sudan, 2002–14 (PDF). HSBA Working Paper 37. Small Arms Survey. pp. 69–70. ISBN 978-2-940548-11-8. Archived (PDF) from the original on 10 June 2016. Retrieved 7 February 2019.
- Conflict Armament Research 2014, pp. 12–13.
- Conflict Armament Research (September 2014). Islamic State Weapons in Iraq and Syria: Analysis of weapons and ammunition captured from Islamic State forces in Iraq and Syria (PDF). p. 7. Archived (PDF) from the original on 26 August 2018. Retrieved 31 August 2018.
- "Arming the Maute Group in Marawi City – The Firearm Blog". The Firearm Blog.com. 22 June 2017. Archived from the original on 14 November 2017. Retrieved 16 January 2018.
- Hogg, Ian V.; Weeks, John S. (2000). Military Small Arms of the 20th Century (7th ed.). Iola, Wisconsin: Krause Publications. ISBN 978-0-87341-824-9., p. 291
- "Customers / Weapon users". Colt Defense Weapon Systems. Archived from the original on 2 September 2011.
- "The AR is not Direct Gas Impingement". Retrieved 30 March 2020.
- "M855A1 Enhanced Performance Round (EPR), LTC Philip Clark, Product Manager Small Caliber Ammunition, April 2012" (PDF). Acc.dau.mil. Archived from the original (PDF) on 25 January 2017. Retrieved 25 February 2017.
- "M16A2/A4 rifle". peosoldier.army.mil. Archived from the original on 24 July 2014. Retrieved 29 July 2015.
- "M16/A2 – 5.56 mm Semiautomatic Rifle". ArmyStudyGuide.com. Archived from the original on 6 July 2014. Retrieved 13 July 2014.
- Smith, Walter H.B. (May 1990). Ezell, Edward Clinton (ed.). Small Arms of the World (12th ed.). New York: Stackpole Books. pp. 46–47. ISBN 978-0880296014.
- Urdang, p. 801.
- Osborne, Arthur D.; Smith, Seward (February 1986). "ARI Research Note 86-19, ANALYSIS OF M16A2 RIFLE CHARACTERISTICS AND RECOMMENDED IMPROVEMENTS" (PDF). Mellonics Systems Development Division, Litton Systems, Inc. Fort Benning, Georgia: ARI Field Unit, Training Research Laboratory, United States Army – Research Institute for the Behavioral and Social Sciences. Archived from the original (PDF) on 29 March 2017.
- Venola p. 6-18
- Green, Michael (13 March 2004). Weapons of the Modern Marines. MBI Publishing Company. p. 16.
- "M16 5.56mm Rifle". Colt.com. 2 June 2003. Archived from the original on 2 June 2003.
- "Small Arms–Individual Weapons" (PDF). 3 November 2010. Archived (PDF) from the original on 9 February 2011. Retrieved 8 November 2010.
- "Commandant approves M4 as standard weapon for Marine infantry". Military Times. 26 October 2015. Archived from the original on 9 May 2017.
- Fallows, James (1 June 1981). "M-16: A Bureaucratic Horror Story". The Atlantic. Archived from the original on 1 April 2019. Retrieved 1 April 2019.
- Ehrhart, Major Thomas P. (2009). "Increasing Small Arms Lethality in Afghanistan: Taking Back the Infantry Half-Kilometer" (PDF). U.S. Army. Archived from the original on 19 July 2013.
- Rottman 2011, p. 6
- Schreier, Philip (September 2001). "Cut down in its Youth, Arguably Americas Best Service Rifle, the M14 Never Had the Chance to Prove Itself" (PDF). NRA Museum. pp. 24–29, 46. Archived from the original (PDF) on 4 December 2013. Retrieved 3 June 2019.
- Thompson, Leroy (2011). The M1 Carbine. Osprey. p. 35. ISBN 978-1-84908-907-4.
- "Arms of the Chosin Few". American Rifleman. Archived from the original on 5 December 2013. Retrieved 23 November 2011.
- Hall, Donald L. (March 1952). "An effectiveness study of the infantry rifle" (PDF). Ballistic Research Laboratories. Maryland: Released 29 March 1973. Archived from the original (PDF, Report No. 593) on 24 September 2015.
- Fanaticism and Conflict in the Modern Age, by Matthew Hughes & Gaynor Johnson, Frank Cass & Co, 2005
- "An Attempt To Explain Japanese War Crimes". Pacificwar.org.au. Archived from the original on 7 July 2012. Retrieved 23 August 2012.
- "South to the Naktong – North to the Yalu". History.army.mil. Archived from the original on 7 February 2014. Retrieved 23 August 2012.
- "HyperWar: The Big 'L'-American Logistics in World War II". Ibiblio.org. Archived from the original on 3 December 2013. Retrieved 24 December 2011.
- "The Logistics of Invasion". Almc.army.mil. Archived from the original on 22 June 2015. Retrieved 23 November 2011.
- Harrison (NRA Technical Staff), E. H. (Col.) (June 1957). "New Service Rifle" (PDF). Archived from the original (PDF) on 7 November 2015.
- Williams, Anthony G. (3 February 2012). "Assault Rifles And Their Ammunition: History and Prospects". Quarry.nildram.co.uk. Archived from the original on 2 June 2014. Retrieved 23 November 2011.
- Pikula, pp. 36, 38
- Pikula, Major Sam. The ArmaLite AR-10. Regnum Fund Press, 1998. ISBN 9986-494-38-9. pp. 27-29
- Pikula, Sam (Major), The ArmaLite AR-10, p. 38: Later changed to titanium.
- Pikula, pp. 27-30
- Lewis, Jack (1963). "The M-14: Boon or Blunder". Gun World. 3 (4).
- Pikula, pp. 39-40
- Bruce, Robert (April 2002). "M14 vs. M16 in Vietnam". Small Arms Review. 5 (7). Archived from the original on 22 April 2016. Retrieved 3 June 2019.
- "The M14". Jane's International Defense Review. 36: 43. 2003.
The M14 is basically an improved M1 with a modified gas system and detachable 20-round magazine.
- "M14 7.62mm Rifle". Globalsecurity.org. 20 September 1945. Archived from the original on 9 November 2014. Retrieved 23 November 2011.
- Emerson, Lee (10 October 2006), M14 Rifle History and Development (PDF), archived from the original (PDF) on 15 December 2017, retrieved 3 June 2019
- Rottman 2011, p. 41
- Hutton, Robert (1971). The .223. Guns & Ammo Annual ed.
- Kern, Danford Allan (2006). "The influence of organizational culture on the acquisition of the m16 rifle" (PDF). m-14parts.com. Fort Leavenworth, Kansas: A thesis presented to the Faculty of the US Army Command and General Staff College in partial fulfillment of the requirements for the degree MASTER OF MILITARY ART AND SCIENCE, Military History. Archived from the original (PDF) on 5 November 2013.
- Kokalis, Peter G. "Retro AR-15" (PDF). Nodakspud.com. Archived from the original (PDF) on 29 October 2013.
- "Hearings before the Special Subcommittee on the M-16 Rifle Program of the Committee on Armed Services, House of Representatives, Ninetieth Congress, first session, 15 May, 16, 31, 21 June, 25 July, 26, 27, 8 August, 9, and 22, 1967". U.S. House of Representatives. p. 4545. Retrieved 1 April 2019.
- GX. The Guard Experience. The Pride of the Guard. by Major Darrin Haas. Volume 10. Issue 3. 2013. Page 67. "Nicknamed a 'Mattel toy' because of its small caliber and lightweight design, the M16 became the standard service rifle for U.S. forces in Vietnam in 1967. The weapon was much lighter compared to the M14 it replaced, ultimately allowing Soldiers to carry more ammunition. The air-cooled, gas-operated, magazine-fed assault rifle was made of steel, aluminum alloy and composite plastics, truly cutting-edge for the time. Designed with full and semi-automatic capabilities, the weapon initially did not respond well to wet and dirty conditions, sometimes even jamming in combat. After a few minor modifications, the weapon gained in popularity among troops on the battlefield. Still in service today, the M16 is being phased out by the M4 carbine.
- "Report of the M16 Review Panel" (PDF), Department of the Army, M16 Surveys in the Republic of Vietnam, Washington DC: Office of the Deputy Chief of Staff for Research, Development, Acquisition, 1 June 1968, archived (PDF) from the original on 4 March 2016, retrieved 3 June 2019
- Small Arms. By Martin J. Dougherty. The Rosen Publishing Group, 15 December 2012. page 26
- Arvidsson, Per G. "Weapons & Sensors" (PDF). NATO Army Armaments Group. Archived from the original (PDF) on 24 September 2015.
- Valpolini, Paolo (February 2012). "Special Ops & Soldier Small Arms, Sights & Accessories" (PDF). Assault Rifles. Compendium Special Operations by Armada. Archived from the original (PDF) on 3 December 2013. Retrieved 27 July 2013.
Among western armies the M4 with its 356-mm-long barrel remains the benchmark type, although reports from the field have shown some criticism regarding its reliability in sand and dusty environments due to the direct impingement or 'gas-tube' system that tends to bring carbon blow-back into the chamber, while hot gases used to cycle the weapon generate heat problems
- Scott R. Gourley (July 2008). "Soldier Armed. M16A4 Rifle" (PDF). Army Magazine: 75. Archived (PDF) from the original on 23 September 2015. Retrieved 11 January 2018.
Colt literature notes that the fourth generation of the M16 "still represents the world standard by which all other weapons of this class are judged. Its combat-proven performance is verified by the fact that over eight million M16 weapon systems have been produced and placed in military service throughout the world.
- "Army Drops Colt as M16 Rifle Maker". The New York Times. 3 October 1988. Archived from the original on 25 April 2019.
- Rose 2009, p. 372
- Rose 2009, pp. 372–373
- "Ammo Oracle". Ammo.ar15.com. Archived from the original on 7 July 2011. Retrieved 27 September 2011.
- Rose 2009, p. 373
- "RESEARCH & DEVELOPMENT FIELD UNIT. Advanced Research Projects Agency. REPORT OF TASK NO. 13A. TEST OF ARMALITE RIFLE. AR-15 (U)" (PDF). Assets.documentcloud.org. 31 July 1962. Retrieved 16 January 2018.
- Sweeney, Patrick (28 February 2011). Modern Law Enforcement Weapons & Tactics (3rd ed.). Iola, Wisconsin: Krause Publications. p. 240. ISBN 978-1-4402-2684-7. Archived from the original on 27 September 2013. Retrieved 6 June 2013.
- Rose 2009, pp. 380, 392
- Rose 2009, p. 380
- C.H. Chivers (2 November 2009). "How Reliable is the M16 Rifle?". The New York Times. Archived from the original on 22 July 2011. Retrieved 12 January 2011.
- "Defense: Under Fire". Time (9 June 1967). 9 June 1967. Archived from the original on 1 May 2010. Retrieved 28 September 2009.
- United States Department of the Army; Robert A. Sadowski (2013). The M16A1 Rifle: Operation and Preventive Maintenance. Skyhorse Publishing. ISBN 978-1-61608-864-4. Archived from the original on 26 March 2019. Retrieved 13 July 2014.
- Rottman 2011, p. 79
- Full text of "DA Pam 750-30". 28 June 1968. Retrieved 13 July 2014.
- Smith, Walter H.B. (May 1990). Ezell, Edward Clinton (ed.). Small Arms of the World (12th ed.). New York: Stackpole Books. pp. 746–762. ISBN 978-0880296014.
- Watters, Daniel E. "The Great Propellant Controversy". The Gun Zone. Archived from the original on 22 July 2013. Retrieved 29 June 2013.
- Hearings, Reports and Prints of the House Committee on Armed Services, Issue 14, Part 1. United States. Congress. House. Committee on Armed Services. U.S. Government Printing Office. 1969. p. 2326.
- "ARMALITE TECHNICAL NOTE 54: DIRECT IMPINGEMENT VERSUS PISTON DRIVE" (PDF). Armalite. 3 July 2010. Archived from the original (PDF) on 17 May 2012.
- Kahaner, Larry (2007). AK-47: The Weapon that Changed the Face of War. Wiley. p. 236. ISBN 978-0-470-16880-6.
This was dubbed the Ichord hearings after Missouri representative Richard Ichord, who championed Congress's inquiry into failures of the M-16 during the Vietnam War.
- Hallock, Colonel Richard R. (retired) US Army (16 March 1970). "M16 Case Study" (PDF). Pogo Archives.org. Archived from the original (PDF) on 6 September 2015.
- Rottman 2011, p. 30
- "Technical note 48: the effects of barrel design and heat on reliability" (PDF). Armalite. 24 August 2003. Archived from the original (PDF) on 11 November 2011.
- "The USA's M4 Carbine Controversy". Defense Industry Daily. 21 November 2011. Archived from the original on 13 July 2007. Retrieved 24 December 2011.
- Jenkins, Shawn T., Major, United States Army; Lowrey, Douglas S., Major, United States Army (December 2004). "A COMPARATIVE ANALYSIS OF CURRENT AND PLANNED SMALL ARMS WEAPON SYSTEMS" (PDF). NAVAL POSTGRADUATE SCHOOL. Submitted in partial fulfillment of the requirements for the degree of MASTER OF BUSINESS ADMINISTRATION. Archived from the original on 22 July 2013. Retrieved 20 November 2015.CS1 maint: multiple names: authors list (link)
- Russell, Sara M. (December 2006). "Soldier Perspectives on Small Arms in Combat" (PDF). CNA Corporation. Archived from the original (PDF) on 31 August 2015. Retrieved 13 July 2014. Cite journal requires
- "Brownells shipping M16 magazines with anti-tilt follower to military". The Firearm Blog. 13 June 2009. Archived from the original on 21 September 2013.
- "New US Army M16 "Tan" Magazine". The Firearm Blog. 16 December 2009. Archived from the original on 21 September 2013.
- "Army begins shipping improved 5.56mm cartridge". Picatinny Arsenal. 24 June 2010. Archived from the original on 1 June 2013.
- "Examining the Complaints About American Rifle Reliability". The New York Times. 7 July 2010. Archived from the original on 22 September 2013.
- Operator's Manual M16A1 Rifle Archived 20 April 2012 at the Wayback Machine. flii.by
- Field Manual No. 23-8, U.S. RIFLE 7.62MM, Ml4 AND M14E2, HEADQUARTERS, DEPARTMENT OF THE ARMY, Washington, D.C., 7 May 1966 Archived 18 April 2015 at the Wayback Machine
- "Ak 47 Technical Description – Manual". Scribd.com. 30 September 2010. Archived from the original on 28 March 2012. Retrieved 23 August 2012.
- "ARMY TM 9-1005-319-10, AIR FORCE TO.11W3-55-41, NAVY SW 370-BUJ-OPl-010 : Supersedes copy dated August 1986 : OPERATOR'S MANUAL FOR RIFLE, 5.66 MM, M16A2 W/E (1005-01-128-9936) (EIC:4GM) RIFLE, 5.56 MM, M16A3 (1005-01-367-5112) RIFLE, 5.56 MM, M16A4 (1005-01-383-2872)( EIC:4F9) CARBINE, 5.56 MM, M4 W/E (1005-01-231-0973) (EIC:4FJ) CARBINE, 5.56 MM, M4A1 (1005-01-382-0953) (EIC:4GC)" (PDF). Larcpistolandrifleclub.com. 1 October 1998. Archived from the original (PDF) on 7 November 2015. Retrieved 16 January 2018.
- Simpson, Layne (4 January 2011). "Handloading The .223 Remington for the AR-15". Shootingtimes.com. Archived from the original on 3 December 2013. Retrieved 13 July 2014.
- Army Technical Manual (for M16 rifle) – TM 9-1005-249-23P. Archive.org. United States Army. Retrieved 13 July 2014.
- Military Small Arms of the 20th Century, 7th Edition, 2000 by Ian V. Hogg & John S. Weeks. P 292
- "Wayback Machine" (PDF). 5 June 2003. Archived from the original (PDF) on 5 June 2003.
- "Recoil Calculator". kwk.us. Archived from the original on 17 October 2018. Retrieved 3 June 2019.
- "Initial Adjustments - Low Light Level Sight System" (Section II). Operator's Manual For M16, M16A1. pp. 2–17. Retrieved 27 September 2011.
- "2-9 Initial Adjustments - Low Light Level Sight System" (Section II). Operator's Manual For M16, M16A1. pp. 1–3. Retrieved 8 October 2011.
- Venola, Richard (2005). What a Long Strange Trip It's Been, Book of the AR-15. 1 (2 ed.). pp. 6–18.
- Henderson, Ronald. "Company's Successful M68 Close Combat Optic Standard Issue Equipment For US Forces Since 1997". Armed Forces International. Archived from the original on 9 December 2011. Retrieved 9 February 2012.
- "Fiscal Year (FY) 2005 BUdget Estimates: Procurement of Ammunition" (PDF). United States Department of the Air Force. February 2004. Archived from the original (PDF) on 22 September 2013. Retrieved 13 July 2014. Cite journal requires
- "History – Trijicon, Inc". Trijicon.com. Archived from the original on 30 June 2012. Retrieved 9 February 2012.
- "Marines Pleased, So USMC Orders $660M More ACOG Rifle Scopes". Defense Industry Daily. 15 August 2005. Archived from the original on 22 November 2012. Retrieved 9 February 2012.
- Hopkins, Cameron (24 April 2009). "Colt's M4A1 5.56mm Carbine". Tactical-Life.com. Archived from the original on 25 June 2012. Retrieved 3 April 2012.
- Glenn Newick (October 1990). The Ultimate in Rifle Accuracy. Stoeger Publishing Company. pp. 26–27. ISBN 978-0-88317-159-2.
- Lucas A. Dyer (May 2014). A Battle Won by Handshakes. iUniverse. p. 122. ISBN 978-1-4917-3200-7.
- Hans Halberstadt (18 March 2008). Trigger Men: Shadow Team, Spider-Man, the Magnificent Bastards, and the American Combat Sniper. St. Martin's Press. pp. 211–212. ISBN 978-0-312-35456-5.
- Rottman 2011, p. 38
- Sweeney, Patrick. Gun Digest Book of the AR-15, Volume 2[page needed]
- "Marine sniper metes out swift death in Iraq's most dangerous neighborhood". USA Today. 29 July 2006. Archived from the original on 24 May 2019. Retrieved 20 November 2015.
- Avtomat Kalashnikov Archived 13 May 2012 at the Wayback Machine. Alpharubicon.com. Retrieved on 3 April 2012.
- Taylor, Chuck. (13 June 2009) Tactical Life. In Praise of the M16 Rifle. Why it's become the longest serving rifle in the recent US military history! "From an accuracy standpoint, there is no comparison between the M16 and AK. As long as the upper and lower receivers are tight and the trigger is halfway decent, the M16 is capable of MOA accuracy, whereas a typical AK will produce 5 to 6 MOA at best. And, if a free-floated barrel is incorporated to the M16's design, it becomes capable of ½-MOA or better, making it fully as accurate as a finely tuned heavy-barreled bolt-action precision rifle."
- Venola, Richard. "Iraq: Lessons From The Sandbox". Combat Arms. ISSN 0810-8838.
- Woods, Jeffrey K. LTC. "The Evolution of the M855A1 5.56mm Enhanced Performance Round, 1960–2010" (PDF). Picatinny Arsenal (October–December 2010). ARMY AL&T. pp. 32–35. Archived from the original (PDF) on 21 September 2013.
- Kjellgren, G. L. M. "The Practical Range of Small Arms" (PDF). The American Rifleman. pp. 40–44. Archived (PDF) from the original on 5 March 2015.
- The Complete Encyclopedia of Automatic Army Rifles, A.E. Hartink, Hackberry Press 2001
- Chivers, C. J. (12 October 2010). The Gun (1st ed.). Simon and Schuster Publishing. p. 206. ISBN 978-0743270762.
Taken from the Long Range Dispersion Firing Test of the AK-47 Assault Rifle, U.S. Army Foreign Science and Technology Center. August 1969. "Just how mediocre? Two decades later, the U.S. Army would hold long-range firing tests with Kalashnikov variants, including three Soviet, two Chinese, and a Romanian model. At 300 meters, expert shooters at prone or bench rest positions had difficulty putting ten consecutive rounds on target. The testers then had the weapons fired from a cradle by a machine, which removed human error. At 300 meters, the ten-rounds group fired in this manner had a minimum dispersion of 17.5 inches, compared to the 12.6 inches with an M-16, the American assault rifle fielded in Vietnam as a reaction to the Kalashnikov's spread
- Dictionary of Military and Associated Terms. US Department of Defense 2005
- Ingalls, James Monroe (1893) Ballistics. U.S. Government Printing Office. p. 7
- "22 Long Rifle 40 gr. Super-X". Winchester.com. Archived from the original on 3 February 2013. Retrieved 20 November 2015.
- Weaver, Jr., Jonathan M. LTC, Infantry, U. S. Army (Retired) (May 1990). "System Error Budgets, Target Distributions and Hitting Performance Estimates For General-Purpose Rifles and Sniper Rifles of 7.62 X 51 MM and Larger Calibers" (PDF). Defense Technical Information Center. U. S. Army Material Systems Analysis Activity. Archived (PDF) from the original on 23 November 2015.CS1 maint: multiple names: authors list (link)
- Steve Crawford (2003). Twenty First Century Small Arms: The World's Great Infantry Weapons. Zenith Imprint. pp. 85–86. ISBN 978-0-7603-1503-3. Retrieved 6 June 2013.
- Rose 2009, pp. 375–376
- McNab, Chris (2002). The SAS Training Manual, pp. 108–109.
- "Scientific Evidence for 'Hydrostatic Shock'", Michael Courtney and Amy Courtney, (2008)
- Fackler, Martin L. MD. "The Effects of Small Arms on the Human Body" (PDF). Archived from the original (PDF) on 7 June 2016. Retrieved 27 September 2011.
- "Patterns of Military Rifle Bullets". Ciar.org. Archived from the original on 20 November 2012. Retrieved 23 August 2012.
- "Rifle Evaluation Study". U.S. Army, Infantry Combat Developments Agency. 17 February 1978. Archived from the original on 1 December 2012.
- Slepyan, L.I.; Ayzenberg-Stepanenko, M.V. (1998). "PENETRATION OF METAL-FABRICS COMPOSITES BY SMALL PROJECTILES" (PDF). Personal Armour Systems. British Crown Copyright/MOD The Institute for Industrial Mathematics. Archived from the original (PDF) on 7 November 2015.
- Parks, W. Hays (2010). "International Legal Initiatives to Restrict Military Small Arms Ammunition" (PDF). Defense Technical Information Center (DTIC). International Committee of the Red Cross (ICRC). pp. 1–18. Archived from the original (PDF) on 29 November 2011.
Those who consider the M16 inhumane include; the International Committee of the Red Cross, Austria, Argentina, Belgium, Bolivia, Bulgaria, Burundi, Cambodia, Cyprus, Germany, Ireland, Latvia, Lithuania, Luxembourg, Mauritius, Mexico, Romania, Samoa, Slovenia, Sweden, Switzerland, etc.
- Ian V. Hogg; John S. Weeks (2000). Military Small Arms of the 20th Century. Krause Publications. ISBN 978-0-87341-824-9. Archived from the original on 3 January 2014. Retrieved 27 September 2011.
- Prokosch, Eric (31 August 1995). "The Swiss draft Protocol on Small-Calibre Weapon Systems". Icrc.org. International Review of the Red Cross. Archived from the original on 7 July 2015. Retrieved 20 November 2015.
- "The M-16 Argument Heats Up, Again". The New York Times. November 3, 2009. Archived from the original on June 16, 2013.
- "M4 5.56mm Carbine". Colt.com. Archived from the original on 16 June 2011. Retrieved 8 October 2011.
- "Project manager soldier weapons soldier weapons assessment team report 6-03" (PDF). Archived from the original (PDF) on 14 July 2011. Retrieved 8 October 2011.
- Dean, Glenn; LaFontaine, David. "Small Caliber Lethality: 5.56 Performance in Close Quarters Battle" (PDF). WSTIAC Quarterly. 8 (1): 3. Archived from the original (PDF) on 12 February 2012.
- Arvidsson, Per (6 January 2012). "Is there a Problem with the Lethality of the 5.56 NATO Caliber?". Small Arms Defense Journal. Archived from the original on 12 October 2013. Retrieved 20 November 2015.
- Rose, Alexander (2009). American Rifle: A Biography. Delta. pp. 403–405. ISBN 978-0-553-38438-3.
- "Evolution of the M855A1 Enhanced Performance Round". U.S. Army. The United States Army. Archived from the original on April 20, 2014. Retrieved November 19, 2011.
- "The current readiness of the U.S. forces: hearing before the Subcommittee on Readiness and Management Support of the Committee on Armed Services, United States Senate, One Hundred Eleventh Congress, second session, April 14, 2010" (PDF). Washington: U.S. Government Printing Office. 14 April 2010. Archived from the original (S. HRG. 111–868) on 10 March 2017.
- Slowik, Max (6 September 2012). "New M855A1 Enhanced Performance Round smashing expectations". Archived from the original on 3 December 2013.
- Slowik, Max (25 July 2013). "Army Speeding M855A1 EPR Adoption, 7.62 NATO Variant in the Works". Archived from the original on 29 June 2017.
The U.S. Army is hastening their adoption of the new M855A1 Enhanced Performance Round, a new 5.56 NATO cartridge that's designed specifically for M4 carbines. The Army has been so impressed with the new round that they're now developing a 7.62 NATO variant. The cartridge is also both environmentally and soldier-friendly
- "DEVASTATING New M80A1 7.62mm Round". TheFirearmBlog. Archived from the original on 22 October 2018.
- "Taking a Look Inside the Army's DEVASTATING New M80A1 7.62mm Round". TheFirearmBlog. Archived from the original on 22 October 2018.
- Bartocci, Christopher R. (20 July 2011). "Feeding the Modern Semi-Automatic Rifle". Americanrifleman.org. Archived from the original on 14 April 2013. Retrieved 23 August 2012.
- Ehrhart, Thomas P. (2009). "Increasing Small Arms Lethality in Afghanistan: Taking Back the Infantry Half-Kilometer". School of Advanced Military Studies. Fort Leavenworth, Kansas: United States Army Command and General Staff College. Archived from the original on 6 September 2013.
- Crane, David (3 December 2010). "SureFire "Quad-Stack" AR Rifle Magazines: SureFire 60-Shot and 100-Shot AR (AR-15/M16) 5.56mm NATO Box Magazines for Significantly-Increased Firepower during Infantry Combat and Tactical Engagements of All Sorts: Meet the SureFire MAG5-60 and MAG5-100 High Capacity Magazines (HCMs)"Quad-Stack" AR Rifle Magazines: 60-Round/Shot and 100-Round/Shot AR (AR-15/M16) 5.56mm NATO Box Magazines for Significantly-Increased Firepower during Infantry Combat and Tactical Engagements of All Sorts". Defense Review. Archived from the original on 21 March 2015.
Standard MILSPEC USGI 30-Round Magazine Specs (data provided by SureFire): Height: 7.1" and Weight-Empty: 3.9 ounces
- Crane, David (23 January 2009). "Lancer Systems L5 Translucent Polymer 30-Round Magazine for Tactical ARs]". Defense Review. Archived from the original on 3 July 2018.
- "Heckler Koch HK416 Enhanced Carbine 556x45mm NATO". Archived from the original on 3 December 2013. Retrieved 9 September 2017. |HK high-reliability 30-round steel magazine fact sheet
- Rottman 2011, pp. 35–36
- Future Weapons, Kevin Dockery, Penguin, 2007, pp. 125-126.
- "Article includes a magazine animation". Peo Soldier Live. 14 December 2009. Archived from the original on 24 February 2013. Retrieved 24 December 2011.
- PEO Soldier. "Improved magazine increases weapons reliability". Picatinny Arsenal. The United States Army. Archived from the original on 22 September 2013. Retrieved 24 December 2011.
- "First Look – New US Army 30 Round Enhanced Performance Magazine for M4A1". Soldier Systems Daily. 8 August 2016. Archived from the original on 7 September 2016. Retrieved 31 August 2016.
- Sweeney, Patrick (2012). Gun Digest Book of the AR-15. Iola, Wisconsin: Gun Digest Books. p. 67. ISBN 978-1-4402-2868-1.
- Wieland, Terry (22 November 2011). Gun Digest Book of Classic American Combat Rifles. Iola, Wisconsin: Krause Publications. p. 100. ISBN 978-1-4402-3017-2.
- Hansen, Denny (2005). "Flash Hiders, is there a difference?". SWAT. 24 (2): 28–32.
- NATO Stock Number of NSN 1005-01-591-5825, PN 1001V
- "NSN 1005-01-591-5825". Archived from the original on 22 September 2013. Retrieved 6 June 2013.
- "Colt Canada Corporation". 212. Archived from the original on 22 September 2013. Retrieved 6 June 2013.
- Sweeney, Patrick (11 August 2010). "21". The Gun Digest Book of The AR-15. Iola, Wisconsin: Gun Digest Books. pp. 255–256. ISBN 978-1-4402-1622-0. Retrieved 6 June 2013.
- Walker, Robert E. (2012). Cartridges and Firearm Identification. Florence, KY: CRC Press. p. 295. ISBN 978-1-4665-0206-2.
- RIFLE, 5.56-MM, XM16E1. Headquarters, Department of the Army, 12 July 1966 p.4
- Technical Manual: Organizational, Direct Support, and General Support Maintenance Manual (Including Repair Parts and Special Tools List): Rifle, 5.56-mm, M16 (1005-00-856-6885): Rifle, 5.56-mm, M16A1 (1005-00-073-9421). Headquarters, Department of the Army. 25 November 1983 p. 1-3
- The Mechanized Infantry Platoon and Squad (APC). Headquarters, Department of the Army. March 1985. p. B-1
- "M16 5.56mm Rifle". Colt.com. Archived from the original on 16 June 2011. Retrieved 8 October 2011.
- Watters, Daniel. "The 5.56 X 45mm Timeline: A Chronology of Development". The Gun Zone. 2000–2007. Archived from the original on 16 March 2015.
- "NATO Infantry Weapons Standardization" (PDF). NDIA Conference. 2008. Archived from the original (PDF) on 1 December 2012.
- "Mecar rifle grenades". Mecar.be. 28 August 2006. Archived from the original on 18 March 2014. Retrieved 13 July 2014.
- "SAS Weapons". Special Operations.Com. United Kingdom. 2000. Archived from the original on 12 July 2008.
- "Defense.gov Photos : News Photo". Defense.gov. 1 March 2010. Archived from the original on 1 March 2010.
- "Sgt. Zachary Sarver and Spc. Gary Vandenbos negotiate with a role-playing inebriated woodsman during Exercise Peaceshield 2000". Defense.gov. 2000. Archived from the original on 9 November 2004. Retrieved 9 November 2004.
- "Navy.mil – View Image". Navy.mil. 29 December 2017. Archived from the original on 29 December 2017.
- Venola, Richard (2005). "What a Long Strange Trip It's Been". Book of the AR-15. 1 (2): 6–18.
- Hogg & Weeks 2000, p. 292
- David Miller (November 2002). The Illustrated Directory of Special Forces. Zenith Imprint. p. 280. ISBN 978-0-7603-1419-7. Archived from the original on 28 September 2013. Retrieved 6 June 2013.
- M16 4-Way Selector Install (and everything you ever wanted to know about 3 and 4-way burst kits) Archived 30 June 2017 at the Wayback Machine. Robrobinette.com. Retrieved: 20 November 2015.
- "National Guard rifleman" (Photo). Archived from the original on 16 December 2018. Retrieved 14 December 2018.
- "US Navy, Marines Buy M-16 Rifles". Defense Industry Daily. 2 January 2008. Archived from the original on 5 January 2008. Retrieved 3 January 2008.
- "CHAPTER 2 - CHARACTERISTICS, AMMUNITION, AND ACCESSORIES". US Army Field Manual: RIFLE MARKSMANSHIP M16A1, M16A2/3, M16A4 and M4 CARBINE. 24 April 2003. Archived from the original on 7 March 2010. Retrieved 11 June 2010.
- "Deadlier rifles and ammo may be on the way". Marine Corps Times. 16 February 2015. Archived from the original on 8 July 2017.
- "Marines unveil plan to modernize their small arms arsenal". Marine Corps Times. 17 September 2015. Archived from the original on 5 January 2016.
- "Marine brass endorses infantry plan to ditch M16 for M4". Military Times. 27 July 2015. Archived from the original on 30 July 2015.
- "Marine grunts react to switch from the M16 to the M4". Marine Corps Times. 1 November 2015. Archived from the original on 25 April 2016.
- Canadian Forces Automatic Rifles Archived 6 July 2011 at the Wayback Machine. Canadian American Strategic Review. Retrieved: 23 August 2009.
- "Face Time With the HK416 – The Gun That Killed Bin Laden". Popular Mechanics. Archived from the original on 8 May 2017. Retrieved 20 November 2015.
- "The Gun That Killed Osama bin Laden Revealed". U.S. News. 11 May 2011. Archived from the original on 26 June 2011. Retrieved 20 November 2015.
- "S-5.56 rifle technical specifics table". Archived from the original on 30 June 2017. Retrieved 7 October 2007.
- "Product Details: Terab". Archived from the original on 10 January 2017. Retrieved 16 November 2016.
- "M16 – WAC-47 for Ukrainian army from UkrOboronProm" (Press release). UkrOboronProm. 10 January 2017. Archived from the original on 18 January 2017. Retrieved 10 January 2017.
- "Ukraine's Plan to Manufacture US M16 Rifles Hits a Snag". dailysignal.com. 11 January 2017. Archived from the original on 14 January 2017. Retrieved 23 January 2017.
- "Afghan National Security Forces Order of Battle" (PDF). Long War Journal. Archived (PDF) from the original on 7 June 2012. Retrieved 3 November 2011.
- "Exposición del Ejército Argentino en Palermo, Buenos Aires- Mayo de 2005". Archived from the original on 22 January 2009. Retrieved 27 September 2011.. saorbats.com.ar
- "Report of the Bahrain Independent Commission of Inquiry" (PDF). Bahrain Independent Commission of Inquiry. 23 November 2011. Archived from the original (PDF) on 19 December 2011. Retrieved 26 December 2011. Cite journal requires
- "Small Arms | Bangladesh Military Forces | BDMilitary.com – The voice of the Bangladesh Armed Forces". BDMilitary.com. Retrieved 22 August 2010.
- Jane's Special Forces Recognition Guide, Ewen Southby-Tailyour (2005) p. 446.
- DH. "Ministarstvo odbrane: Izmjenom propisa vojnici će moći ostati u OSBiH i nakon 35. godine". zeljeznopolje.com. Archived from the original on 28 April 2019. Retrieved 28 April 2019.
- Small Arms Survey (2007). "Enemy Within: Ammunition Diversion in Uganda and Brazil" (PDF). The Small Arms Survey 2007: Guns and the City. Cambridge University Press. p. 309. ISBN 978-0-521-88039-8. Archived from the original on 27 August 2018. Retrieved 29 August 2018.
- Small Arms Survey (2007). "Armed Violence in Burundi: Conflict and Post-Conflict Bujumbura" (PDF). The Small Arms Survey 2007: Guns and the City. Cambridge University Press. p. 204. ISBN 978-0-521-88039-8. Archived from the original on 27 August 2018. Retrieved 29 August 2018.
- "Report: Profiling the Small Arms Industry – World Policy Institute – Research Project". World Policy Institute. November 2000. Archived from the original on 11 October 2017. Retrieved 15 July 2010.
- Wille, Christina (5 May 2011). "How Many Weapons Are There in Cambodia?" (PDF). Small Arms Survey. Archived from the original (Working Paper) on 4 July 2010. Retrieved 27 September 2011.
- Miller, David (2001). The Illustrated Directory of 20th Century Guns. Salamander Books Ltd. ISBN 1-84065-245-4.
- Small Arms Survey (2015). "Waning Cohesion: The Rise and Fall of the FDLR–FOCA" (PDF). Small Arms Survey 2015: weapons and the world (PDF). Cambridge University Press. p. 201. Archived (PDF) from the original on 28 January 2018. Retrieved 29 August 2018.
- Jane's Sentinel Security Assessment – Southeast Asia. Issue 20 – 2007. pp. 146, 152.
- Montes, Julio A. (12 January 2012). "El Salvador: Standing Talls". Small Arms Defense Journal. Vol. 3 no. 4. Archived from the original on 17 April 2019. Retrieved 19 January 2019.
- "Eesti Kaitsevägi – Tehnika – Automaat M-16 A1". Mil.ee. Archived from the original on 3 June 2008. Retrieved 8 September 2008.
- "M16 723 M203". defense.gouv.fr. Ministère des Armées. 13 July 2016. Archived from the original on 30 January 2019. Retrieved 30 January 2019.
- Binnie, Jeremy; de Cherisey, Erwan (2017). "New-model African armies" (PDF). Jane's. Archived from the original (PDF) on 22 June 2017.
- Gander, Terry J.; Hogg, Ian V. Jane's Infantry Weapons 1995/1996. Jane's Information Group; 21 edition (May 1995). ISBN 978-0-7106-1241-0.
- "First steps to arming Iraq's soldiers". BBC News. 18 May 2007. Archived from the original on 11 November 2012. Retrieved 12 May 2010.
- "VIDEO: Peshmerga training with M16 rifles". Rudaw. Archived from the original on 20 March 2018. Retrieved 20 March 2018.
- Pike, John (17 December 2003). "Israel's army phases out country's iconic Uzi submachine gun". Globalsecurity.org. Archived from the original on 12 March 2009. Retrieved 22 August 2010.
- Johnson, Steve (18 December 2012). "IDF Reserve Units Switching From M16 To Tavor". TheFireArmBlog.com. Archived from the original on 30 December 2012.
- Anders, Holger (June 2014). Identifier les sources d'approvisionnement: Les munitions de petit calibre en Côte d'Ivoire (PDF) (in French). Small Arms Survey and United Nations Operation in Côte d'Ivoire. p. 15. ISBN 978-2-940-548-05-7. Archived (PDF) from the original on 9 October 2018. Retrieved 5 September 2018.
- 日本の特殊部隊 (in Japanese). Archived from the original on 4 November 2013.
- "A Weapon Displayed From North Korea Special Forces and their Submarine". MBC News. 25 September 1996. Archived from the original on 20 October 2018. Retrieved 3 June 2019.
- "Equipment of North Korean Special Forces and Espionage". Yu Yong-won's Military World, Chosun Ilbo. 16 April 2013. Archived from the original on 24 May 2015. Retrieved 3 June 2019.
- "wiw_me_kuwait – worldinventory". sites.google.com.
- "wiw_eu_latvia – worldinventory". sites.google.com. Archived from the original on 24 November 2016. Retrieved 15 January 2018.
- McNab, Chris (2002). 20th Century Military Uniforms (2nd ed.). Kent: Grange Books. p. 174. ISBN 978-1-84013-476-6.
- "Lietuvos kariuomenė :: Ginkluotė ir karinė technika »Automatiniai šautuvai» Automatinis šautuvas M-16" (in Lithuanian). Kariuomene.kam.lt. 17 April 2009. Archived from the original on 28 March 2010. Retrieved 22 August 2010.
- "Sauvetage au combat de niveau 1 [SC1] à l'île Maurice" (in French). Forces Armées de la Zone Sud de l'Océan Indien. 12 December 2012. Archived from the original on 22 September 2013. Retrieved 24 October 2013.
- admin. "Mexican Drug War Fighters". Small Arms Defense Journal. Retrieved 7 February 2020.
- "Recession? What Recession? – CNN iReport". CNN. Archived from the original on 1 January 2016.
- Sharma, Sushil (6 January 2003). "Nepal takes delivery of US rifles". BBC News. Archived from the original on 22 September 2013. Retrieved 12 May 2010.
- "Legacies of War in the Company of Peace: Firearms in Nepal" (PDF). Nepal Issue Brief. Small Arms Survey (2): 5–7. May 2013. Archived (PDF) from the original on 8 July 2014. Retrieved 8 January 2019.
- Bartocci, Christopher R. (2004). Black Rifle II The M16 into the 21st Century. Collector Grade Publications Incorporated. ISBN 0-88935-348-4.
- Adnan Abu Amer (10 May 2015). "Security services drain Palestine's budget". Al-Monitor. Archived from the original on 5 May 2017. Retrieved 8 June 2017.
- "In pictures: Gaza offensive". BBC News. 6 November 2006. Archived from the original on 20 March 2018. Retrieved 20 March 2018.
- "Hamas Fighting With Weapons From Israel (Investigation)". 6 January 2009. Archived from the original on 20 March 2018. Retrieved 20 March 2018.
- Capie, David (2004). Under the Gun: The Small Arms Challenge in the Pacific. Wellington: Victoria University Press. pp. 63–65. ISBN 978-0-86473-453-2.
- Ellwood, Justin. "Indo-Pacific Strategic Papers: Understanding the neighbourhood: Bougainville's referendum for independence" (PDF). Australian Department of Defense. pp. 5, 19. Archived (PDF) from the original on 24 March 2018.
- "SPECIAL OPS 3/2015". Archived from the original on 14 May 2018. Retrieved 13 May 2018.
- "World Infantry Weapons: Sierra Leone". 2013. Archived from the original on 24 November 2016.[self-published source]
- "History 'lesson' of note at Arts Festival". Dammam: Knysna-Plett Herald. 6 October 2016. Archived from the original on 22 December 2016. Retrieved 22 December 2016.
- Smith, Chris (October 2003). In the Shadow of a Cease-fire: The Impacts of Small Arms Availability and Misuse in Sri Lanka (PDF). Occasional Paper No. 11. Small Arms Survey. p. 13. Archived (PDF) from the original on 5 July 2017. Retrieved 6 September 2018.
- Henrik Svensk. "M16 M16A2 Kalashnikov AK-47 – Utländska Vapensatsen" (in Swedish). SoldF.com. Archived from the original on 10 April 2016. Retrieved 13 July 2014.
The foreign weapons kit was purchased in 1986 to give personnel in the Armed Forces the opportunity to get to know the weapons that usually show up in war and crisis situations
- "Colt M16A2 Assault Rifle". Military Factory. Archived from the original on 12 November 2014. Retrieved 23 November 2014.
- McNab 2002, p. 243.
- "Royal Military Police train for close protection". Ministry of Defence. 7 August 2012. Archived from the original on 19 October 2015. Retrieved 20 November 2015.
- "SAS Weapons – C8 SFW Carbine L119A1s". EliteUKForces.info. Archived from the original on 19 May 2018. Retrieved 13 December 2012.
- Ripley, Tim (4 March 2016). "UK Royal Marine unit ditches the SA80 for Colt C8". IHS Jane's Defence Weekly. London. Archived from the original on 17 March 2016. Retrieved 13 June 2016.
- "M-16 Rifle Fact File for the United States Army". Army.mil. Archived from the original on 25 August 2010. Retrieved 22 August 2010.
- Ezell, Edward Clinton (1988). Personal firepower. The Illustrated history of the Vietnam War 15. Bantam Books. pp. 152–153. OCLC 1036801376.
- Rottman, Gordon L. (20 December 2011). The M16 (Weapon). Osprey Publishing. p. 34. ISBN 978-1849086905.
With the fall of South Vietnam in April 1975, over 946,000 M16 — type weapons fell into communists hands
- "Australian weapons, Viet Nam and since". Diggerhistory.info. 11 November 2002. Archived from the original on 11 August 2010. Retrieved 22 August 2010.
- "Members of the ZNG's 1st Brigade ("Tiger"), armed with an AK-74, an Anschutz .22 target rifle, and M-16A2s" – via Pinterest. Video on YouTube[better source needed]
- "New Zealand Army Selects LMT To Replace Steyr AUG – The Firearm Blog". Thefirearmblog.com. 18 August 2015. Archived from the original on 24 January 2018. Retrieved 16 January 2018.
- Conboy, Kenneth (23 November 1989). The War in Laos 1960–75. Men-at-Arms 217. Osprey Publishing. p. 15. ISBN 9780850459388.
- Moorcraft, Paul L.; McLaughlin, Peter (April 2008) . The Rhodesian War: A Military History. Barnsley: Pen and Sword Books. ISBN 978-1-84415-694-8.
- Walter, John, Rifles of the World Archived 23 March 2017 at the Wayback Machine, Krause Publications, 2006, illustrated 3rd edition, ISBN 0-89689-241-7, p. 41
- Rottman 2011, p. 34.
- "The Reorganisation of the IRA in the Early 1970s". An Sionnach Fionn. 9 July 2015.
- Modern Warfare, Published by Mark Dartford, Marshall Cavendish (London) 1985
- Afonso, Aniceto and Gomes, Carlos de Matos, Guerra Colonial (2000), ISBN 972-46-1192-2
- Bartocci, Christopher R. Black Rifle II The M16 into the 21st Century. Cobourg, Ontario, Canada: Collector Grade Publications Incorporated, 2004. ISBN 0-88935-348-4
- Ezell, Edward Clinton (1984). The Great Rifle Controversy: Search for the Ultimate Infantry Weapon from World War II Through Vietnam and Beyond. Harrisburg, Pennsylvania: Halsted Press. ISBN 978-0-8117-0709-1.
- Hughes, David R. (1990). The History and Development of the M16 Rifle and its Cartridge. Oceanside, California: Armory Publications. ISBN 978-0-9626096-0-2.
- Hutton, Robert, The .223, Guns & Ammo Annual Edition, 1971.
- McNaugher, Thomas L. "Marksmanship, Mcnamara and the M16 Rifle: Organisations, Analysis and Weapons Acquisition"
- M16 Rifle Review Panel (1 June 1968). "Report of the M16 Rifle Review Panel". Chief of Staff U.S. Army. ADA953110. Cite journal requires
- Pikula, Sam (Major), The ArmaLite AR-10, 1998
- Rose, Alexander. American Rifle-A Biography. 2008; Bantam Dell Publishing. ISBN 978-0-553-80517-8.
- Stevens, R. Blake and Edward C. Ezell. The Black Rifle M16 Retrospective. Enhanced second printing. Cobourg, Ontario, Canada: Collector Grade Publications Incorporated, 1994. ISBN 0-88935-115-5
- Urdang, Laurence, Editor in Chief. The Random House Dictionary of the English Language. 1969; Random House/New York.
- U.S. Army; Sadowski, Robert A., Editor. The M16A1 Rifle: Operation and Preventive Maintenance Enhanced, hardcover edition 2013; Skyhorse, New York, NY. ISBN 1616088648
|Wikimedia Commons has media related to:|
- Colt's Manufacturing: The M16A4 Rifle
- PEO Soldier M16 fact sheet
- AR15.com, the largest M16/AR-15 Resource on the Web
- The Gun Zone: A 5.56 mm Timeline
- The AR-15/M16 Magazine FAQ
- Combat Training with the M16 Manual
- Rifle Marksmanship M16A1, M16A2/3, M16A4 and M4 Carbine (Army Field Manual)
- The short film "The Armalite AR-10" is available for free download at the Internet Archive
- "Army Technical Manual (for M16 rifle) – TM9-1005-249-23P" at the Internet Archive
- "DA Pam 750-30 1969 US Army comic book for maintenance of the M16A1 rifle" at the Internet Archive, artwork by Will Eisner.
- "Operator's Manual for Rifle, 5.56 mm, M16; Rifle 5.56 mm, M16A1" at the Internet Archive
- The short film "Rifle 5.56mm, XM16E1, Operation and Cycle of Functioning TF9-3663 (1966)" is available for free download at the Internet Archive
- The short film "Rifle, M16A1 – Part II – Field Expedients (1 July 1968)" is available for free download at the Internet Archive
- The short film "Fundamentals of Rifle Marksmanship (1971)" is available for free download at the Internet Archive
- The short film "Fundamentals of Rifle Marksmanship (1999)" is available for free download at the Internet Archive
- Operator's Manual for Rifle, 5.56 mm, M16A2; Rifle 5.56 mm, M16A3; Rifle, 5.56 mm, M16A4; Carbine, 5.56 mm, M4; Carbine, 5.56 mm, M4A1
- M16 in parts (German)
- Early M16 rifles