.50 BMG

.50 BMG
From left: .50 BMG, 300 Win Mag, .308 Winchester, 7.62×39mm, 5.56×45mm NATO, .22 Long Rifle
Type	Machine gun/Rifle
Place of origin	United States
Service history
In service	1921–present
Used by	NATO and many other countries
Wars	World War II Korean War Vietnam War Cambodian Civil War Falklands War Persian Gulf War Global War on Terrorism Iraq War War in Afghanistan Syrian Civil War Iraqi Civil War (2014-present) Yemeni Civil War (2015-present) Saudi-led intervention in Yemen (2015-present) Conflict in Najran, Jizan and Asir
Production history
Designer	Winchester Repeating Arms Co. and Frankford Arsenal
Specifications
Parent case	.30-06
Case type	Rimless, bottleneck
Bullet diameter	.510 in (13.0 mm)
Neck diameter	.560 in (14.2 mm)
Shoulder diameter	.735 in (18.7 mm)
Base diameter	.804 in (20.4 mm)
Rim diameter	.804 in (20.4 mm)
Rim thickness	.083 in (2.1 mm)
Case length	3.91 in (99 mm)
Overall length	5.45 in (138 mm)
Case capacity	292.8 gr H2O (18.97 cm3)
Primer type	#35 Arsenal Primer
Maximum pressure (TM43-0001-27)	54,923 psi (378.68 MPa)
Maximum pressure (EPVAT)	60,481 psi (417.00 MPa)
Maximum pressure (C.I.P.)	53,664 psi (370.00 MPa)
Ballistic performance
Bullet mass/type Velocity Energy 647 gr (42 g) Speer 3,044 ft/s (928 m/s) 13,310 ft⋅lbf (18,050 J) 655 gr (42 g) ADI 3,029 ft/s (923 m/s) 13,350 ft⋅lbf (18,100 J) 700 gr (45 g) Barnes 2,978 ft/s (908 m/s) 13,971 ft⋅lbf (18,942 J) 750 gr (49 g) Hornady 2,820 ft/s (860 m/s) 13,241 ft⋅lbf (17,952 J) 800 gr (52 g) Barnes 2,895 ft/s (882 m/s) 14,895 ft⋅lbf (20,195 J)
Test barrel length: 45 in (1,100 mm) Source(s): Ammoguide.com

The .50 Browning Machine Gun (.50 BMG, 12.7×99mm NATO and designated as the 50 Browning by the C.I.P.) is a cartridge developed for the Browning .50 caliber machine gun in the late 1910s. Entering service officially in 1921, the round is based on a greatly scaled-up .30-06 cartridge. Under STANAG 4383, it is a standard cartridge for NATO forces as well as many non-NATO countries. The cartridge itself has been made in many variants: multiple generations of regular ball, tracer, armor-piercing (AP), incendiary, and saboted sub-caliber rounds. The rounds intended for machine guns are linked using metallic links.

The .50 BMG cartridge is also used in long-range target and anti-materiel rifles, as well as other .50-caliber machine guns.

A wide variety of ammunition is available, and the availability of match grade ammunition has increased the usefulness of .50 caliber rifles by allowing more accurate fire than lower quality rounds.

History

John Browning had the idea for this round during World War I in response to a need for an anti-aircraft weapon, based on a scaled-up .30-06 Springfield design, used in a machine gun based on a scaled-up M1919/M1917 design that Browning had initially developed around 1900 (but which was not adopted by the U.S. military until 1917, hence the model designation). Armor-piercing incendiary tracer (APIT) rounds were especially effective against aircraft, and the AP rounds and armor-piercing incendiary (API) rounds were excellent for destroying concrete bunkers, structures, and lighter armored fighting vehicles (AFVs). The API and APIT rounds left a flash, report, and smoke on contact, useful in detecting strikes on enemy targets.

The development of the .50 BMG round is sometimes confused with the German 13.2 mm TuF, which was developed by Germany for an anti-tank rifle to combat British tanks during WWI and against aircraft; however, the development of the U.S. .50 caliber round was started before this later German project was completed or even known to the Allied countries. When word of the German anti-tank round spread, there was some debate as to whether it should be copied and used as a base for the new machine gun cartridge; after some analysis the German ammunition was ruled out, both because performance was inferior to the scaled-up .30-06 Springfield round and because it was a semi-rimmed cartridge, making it sub-optimal for an automatic weapon. The round's dimensions and ballistic traits are totally different.

The round was put into use in the M1921 Browning machine gun. This gun was later developed into the M2HB Browning which with its .50 caliber armor-piercing cartridges went on to function as an anti-aircraft and anti-vehicular machine gun, with a capability of completely perforating 0.875 inches (22.2 mm) of face-hardened armor steel plate at 100 yards (91 m), and 0.75 inches (19 mm) at 547 yards (500 m).

Decades later, the .50 BMG was chambered in high-powered rifles as well. The concept of a .50 caliber machine gun was not an invention of this era; this caliber (.50 inch) had been used in Maxim machine guns and in a number of manual rapid-fire guns such as the original Gatling gun, although these were much lower power cartridges.

The .50 BMG cartridge

During World War II the .50 BMG was primarily used in the M2 Browning machine gun, in both its "light barrel" aircraft mount version and the "heavy barrel" (HB) version on ground vehicles, for anti-aircraft purposes. An upgraded variant of the M2 Browning HB machine gun used during World War II is still in use today. Since the mid-1950s, some armored personnel carriers and utility vehicles have been made to withstand 12.7 mm machine gun fire, thus making it a much less flexible weapon. It still has more penetrating power than lighter weapons such as general-purpose machine guns, though it is significantly heavier and more cumbersome to transport. Its range and accuracy, however, are superior to light machine guns when fixed on tripods, and it has not been replaced as the standard caliber for Western vehicle-mounted machine guns (Soviet and CIS armored vehicles mount 12.7×108mm NSVs, which are ballistically similar to .50 BMGs).

The Barrett M82 .50 caliber rifle and later variants were developed during the 1980s and have upgraded the anti-materiel power of the military sniper. A skilled sniper can effectively neutralize an infantry unit by eliminating several targets (soldiers or equipment) without revealing his precise location. The long range (over one mile) between firing position and target allows time for the sniper to avoid enemy retaliation by either changing positions repeatedly, or by safely retreating.

Power

A common method for understanding the actual power of a cartridge is by comparing muzzle energies. The .30-06 Springfield, the standard caliber for American soldiers in both World Wars and a popular caliber amongst American hunters, can produce muzzle energies between 2,000 and 3,000 foot-pounds of energy (between 3 and 4 kilojoules). The .50 BMG round can produce between 10,000 and 15,000 foot pounds (between 14 and 18 kilojoules), depending on its powder and bullet type, as well as the weapon it was fired from. Due to the high ballistic coefficient of the bullet, the .50 BMG's trajectory also suffers less "drift" from cross-winds than smaller and lighter calibers, making the .50 BMG a good choice for high-powered sniper rifles.

Cartridge dimensions

The .50 BMG (12.7×99mm NATO) cartridge has a capacity of 290 grains H₂O (19 ml). The round is a scaled-up version of the .30-06 Springfield and like .30-06 uses a case wall with a long but relatively "shallow" taper to facilitate feeding and extraction in various weapons. Cartridges are also tapered because bottle-necked rifle cartridges have to have a "shoulder" separating the case body from the neck with that shoulder at an angle. With no body taper the transition to the neck would be much more sudden and sharper and sharp edges and stress risers would result. The taper also provides a "safety backup" for cases that have had their shoulders set back to far and are not properly contacting that area of the chamber and would otherwise be "floating" in the chamber with grossly excessive headspace.

During the 20th century and particularly the second half of the 20th century, the amount of taper on cases reduced dramatically. Most significantly tapered cartridges are rimmed cartridges left over from the blackpowder days when most rifle magazines were tube magazines and cartridge handling/feeding mechanisms simply lifted the cartridge up in front of the chamber with a rolling or tilting breechblock or square/rectangular bolt sealing the breech. Until the cartridge was chambered the bolt/breech block just nudged it toward the chamber mouth. Rimmed cartridges headspaced on the rim, there was no tight seal at the shoulder taper/chamber interfaces and blackpowder cartridges tended to "leak" a great deal of carbon and partially-burned powder residue back into the chamber and around the case. With no case taper bottle-necked cartridges would have quickly started sticking in the chamber or even failing to chamber fully.

Straight-walled rifle cases with no taper such as .45-70 Government sealed very well in their chambers and the tight fit and relatively low pressures allowed them to work fine. Modern rimless smokeless cartridges could have and would have and several do work just fine with very little or no taper because they headspace on the shoulder and seal the chamber. .300 AAC Blackout is an example of a modern bottlenecked cartridge with a shoulder and little or no case taper despite the case being created and "homemade" cases being formed from 5.56x45 NATO/.223 Remington brass.

.50 BMG has case taper because its a scaled-up .30-06 and .30-06 has case taper because it replaced .30-40 Krag at a time when "conventional wisdom" dictated that bottleneck rifle cartridges had to have case taper. In addition to inventing the M2 and .50 BMG cartridge, John Moses Browning invented the first semi-automatic shotguns and sporting rifles and all of the ACP pistol cartridges that all feature straight cases with no taper. There are many situations where case taper can allow a bulged/distorted cartridge case to start into the chamber before jamming and even becoming stuck tight that would be avoided entirely with a straight case. Which is why JMB's ACP pistol cartridges all have straight walls. He invented the cartridges and pistols chambered for them for "self-defense" where a jam could be the difference between life an death.

The common rifling twist rate for this cartridge is 1 in 15 in (380 mm), with eight lands and grooves. The primer type specified for this ammunition is a boxer primer that has a single centralized ignition point (US and NATO countries). However, some other countries produce the ammunition with Berdan primers that have two flash holes.

The average chamber pressure in this round as listed in TM43-0001-27, the U.S. Army Ammunition Data Sheets — Small Caliber Ammunition, not including plastic practice, short cased spotter, or proof/test loads, is 54,923 psi (378,680 kPa). The proof/test pressure is listed as 65,000 psi (450,000 kPa).

Military cartridge types

Left to right, rear: Mk211, spotter, silver tip (armor-piercing incendiary), blue tip (incendiary), black tip (armor piercing), SLAP-T, SLAP, tracer, and ball. Front row are 5.56×45mm NATO and .500 S&W Magnum, for size comparison

The .50 BMG cartridge is also produced commercially with a plethora of different bullets and to a number of different specifications.

Cartridge, caliber .50, tracer, M1

tracer for observing fire, signaling, target designation, and incendiary purposes. This bullet has a red tip.

Cartridge, caliber .50, incendiary, M1

this cartridge is used against unarmored, flammable targets. The incendiary bullet has a light blue tip

Cartridge, caliber .50, ball, M2

this cartridge is used against personnel and unarmored targets. This bullet has an unpainted tip.

Cartridge, caliber .50, armor piercing, M2

this cartridge is used against lightly armored vehicles, protective shelters, and personnel, and can be identified by its black tip

Cartridge, caliber .50, armor-piercing incendiary, M8

this cartridge is used, in place of the armor-piercing round, against armored, flammable targets. The bullet has a silver tip.

Cartridge, caliber .50, tracer, M10

tracer for observing fire, signaling, target designation, and incendiary purposes. Designed to be less intense than the M1 tracer, the M10 has an orange tip.

Cartridge, caliber .50, tracer, M17

tracer for observing fire, signaling, target designation, and incendiary purposes. Can be fired from the M82/M107 series of rifles.

Cartridge, caliber .50, armor-piercing incendiary tracer, M20

this cartridge is used, in place of the armor-piercing round, against armored, flammable targets, with a tracer element for observation purposes. This cartridge is effectively a variant of the M8 armor-piercing incendiary with the added tracer element. Can be fired from the M82/M107 series of rifles. This bullet has a red tip with a ring of aluminum paint.

Cartridge, caliber .50, tracer, headlight, M21

tracer for use in observing fire during air-to-air combat. Designed to be more visible, the M21 is three times more brilliant than the M1 tracer.

Cartridge, caliber .50, incendiary, M23

This cartridge is used against unarmored, flammable targets. The tip of the bullet is painted blue with a light blue ring.

Cartridge, caliber .50, ball, M33

this cartridge is used against personnel and unarmored targets. Can be fired from the M82/M107 series of rifles.

Cartridge, caliber .50, Saboted light armor penetrator, M903

this cartridge has a 355 – 360 gr (23.00 – 23.33 g) heavy metal (tungsten) penetrator that is sabot-launched at a muzzle velocity of 4,000 ft/s (1,219 m/s). The 0.50 in (12.7 mm) diameter sabot is designed to separate after leaving the muzzle, releasing the 0.30 (7.62 mm) penetrator. It is injection molded of special high strength plastic and is reinforced with an aluminum insert in the base section. The cartridge is identified by an amber sabot (Ultem 1000). For use only in the M2 series of machine guns. This round can penetrate 19 mm of steel armor at 1,500 yards (1,400 m).

Cartridge, caliber .50, saboted light armor penetrator tracer, M962

like the M903, this is a SLAP round, with the only difference being that the M962 also has a tracer element for observing fire, target designation, and incendiary purposes. It uses a red plastic sabot for identification. Used only in the M2 series of machine guns.

Cartridge, caliber .50, ball, XM1022

a long-range match cartridge specifically designed for long-range work using the M107 rifle

Cartridge, caliber .50, M1022 long-range sniper

The .50 caliber M1022 has an olive green bullet coating with no tip ID coloration. The projectile is of standard ball design. It is designed for long-range sniper training and tactical use against targets that do not require armor-piercing or incendiary effects. It exhibits superior long range accuracy and is trajectory matched to MK211 grade A. The M1022 is ideal for use in all .50 caliber bolt-action and semi-automatic sniper rifles. The bullet remains supersonic out to from 1,500 m (1,640 yd) to 1,600 m (1,750 yd).

Cartridge, caliber .50, high-explosive armor-piercing incendiary (HEIAP), Mk 211 Mod 0

a "combined effects" cartridge, the Mk 211 Mod 0 HEIAP cartridge contains a .30 caliber tungsten penetrator, zirconium powder, and Composition A explosive. It can be used in any .50 caliber weapon in the US inventory with the exception of the M85 machine gun. The cartridge is identified by a green tip with a gray ring.

Cartridge, caliber .50, armor-piercing incendiary dim tracer (API-DT), Mk 257

the .50 caliber Mk 257 API-DT has a purple bullet tip. The bullet has a hardened steel core and incendiary tip. It is used in the M2, M3, and M85. Dim trace reduces the possibility of the weapon being located during night fire and is visible only with night-vision devices.

Cartridge, caliber .50, armor-piercing (AP), Mk 263 Mod 2

the .50 caliber Mk 265 has a black tip. The bullet has a hardened steel core. It is used in the M2, M3, and M85.

Cartridge, caliber .50, armor-piercing incendiary tracer (API-T), Mk 300 Mod 0

as with the Mk 211 Mod 0, but with a tracer component. This cartridge likely can be used in any .50 caliber weapon in the US inventory with the exception of the M85 machine gun, as with the Mk 211 Mod 0.

Cartridge, caliber .50, armor piercing explosive incendiary (APEI), Mk 169 Mod 2

this cartridge is used against hardened targets such as bunkers, for suppressive fire against lightly armored vehicles, and ground and aerial threat suppression. It is generally fired either from pilot-aimed aircraft-mounted guns or anti-aircraft platforms, both produced by FN Herstal. It is identified by a gray over yellow tip. A tracer variant of it also exists.

Cartridge, caliber .50, ball, Mk 323 Mod 0

created by the Naval Surface Warfare Center Crane Division, this cartridge uses M33 ball projectiles in polymer cases instead of brass. It has a clear polymer case, with a standard brass head fused at the bottom. The Mk 323 can be fired from M2HB/M2A1 machine guns and GAU-21/A aircraft guns with the same performance. It gives a 25 percent weight savings over brass-cased ammunition and allows 40 percent more ammunition to be carried for the same weight. The Mk 323's polymer casing is applied to tracer, AP, API, and SLAP projectiles.

DARPA (Defense Advanced Research Projects Agency) contracted with Teledyne Scientific Company to develop the EXACTO program, including a .50-caliber guided bullet. Videos published by DARPA show the guided bullet diverting to strike a moving target.

Links used for feeding machine guns

Two distinct and non-compatible metallic links have been used for the .50 BMG cartridge, depending upon the machine gun which will be firing the cartridges. The M2 and M9 links, "pull-out" designs, are used in the Browning M2 and M3 machine guns. Pull-out cloth belts were also used at one time, but have been obsolete since 1945. The M15-series "push-through" links were used in the M85 machine gun.

Legal issues

The specified maximum diameter of an unfired .50 BMG bullet is 0.510-inch (13.0 mm); while this appears to be over the .50 inch (12.7 mm) maximum allowed for non-sporting Title I firearms under the U.S. National Firearms Act, the barrel of a .50 BMG rifle is only .50 inch (12.7 mm) across the rifling lands and slightly larger in the grooves. The oversized bullet is formed to the bore size upon firing, forming a tight seal and engaging the rifling, a mechanism which in firearm terms is known as swaging. Subject to political controversy due to the great power of the cartridge (it is the most powerful commonly available cartridge not considered a destructive device under the National Firearms Act), it remains popular among long-range shooters for its accuracy and external ballistics. While the .50 BMG round is able to deliver accurate shot placement (if match grade ammunition is used) at ranges over 1,000-yard (910 m), smaller caliber rifles produce better scores and tighter groups in 1,000-yard (910 m) competitions.

In response to legal action against the .50 BMG in the United States and Europe, an alternative chambering was developed. The .510 DTC Europ uses the same bullet, but has slightly different case dimensions. .510 DTC cases can be made by fire-forming .50 BMG cases in a .510 DTC chambered rifle. The new round has almost identical ballistics, but because of the different dimensions, rifles chambered for .50 BMG cannot fire the .510 DTC, and therefore rifles chambered for .510 DTC do not fall under many of the same legal prohibitions. Barrett offers a similar alternative, the .416 Barrett, which is based on a shortened .50 BMG case necked down to .416 caliber (10.3 mm).

A 1999 Justice Department Office of Special Investigations briefing on .50 caliber rifle crime identified several instances of the .50 BMG being involved in criminal activities. Most of the instances of criminal activity cited in the Office of Special Investigations briefing involved the illegal possession of a .50 BMG rifle. The briefing did not identify any instance of a .50 BMG rifle being used in the commission of a murder.

In the United States of America, California prohibits the private purchase of a rifle capable of firing the .50 BMG through the .50 Caliber BMG Regulation Act of 2004.

Within the United Kingdom, it is legal to own a .50 BMG rifle with a section 1 Firearms Certificate. Applications requesting firearms in this caliber are not subject to any extra scrutiny compared to smaller calibers.

There have been persistent reports of a belief within the United States Armed Forces that using .50 BMG in a direct antipersonnel role is somehow prohibited by the laws of war. This is incorrect and has been characterized as a myth; writing for the Marine Corps Gazette, Maj. Hays Parks states that "No treaty language exists (either generally or specifically) to support a limitation on [the use of .50 BMG] against personnel, and its widespread, longstanding use in this role suggests that such antipersonnel employment is the customary practice of nations." Parks theorizes that the belief originated in historical doctrine discouraging the use of the M8C spotting rifle—an integral .50-caliber aiming aid for the M40 recoilless rifle—in the antipersonnel role. This limitation was entirely tactical in nature and was intended to hide the vulnerable M40 and its crew from the enemy until the main anti-tank gun was ready for firing; however, some personnel evidently assumed the existence of a legal limitation on the use of .50-caliber projectiles more generally.

Typical uses

The primary military use of this round is in the Browning M2HB heavy machine gun.

The U.S. Coast Guard uses .50 BMG rifles to disable outboard engines from armed helicopters during interdictions. Similarly, .50 BMG weapons have attracted attention from law enforcement agencies; they have been adopted by the New York City Police Department as well as the Pittsburgh Police. A .50 BMG round can effectively disable a vehicle when fired into the engine block. If it is necessary to breach barriers, a .50 BMG round will penetrate most commercial brick walls and concrete cinder blocks.

The .50 BMG round has been used as a sniper round as early as the Korean War. The former record for a confirmed long-distance kill was set by U.S. Marine sniper Carlos Hathcock in 1967, at a distance of 2,090 meters (2,290 yd; 1.30 mi); Hathcock used the .50 BMG in an M2 Browning Machine Gun equipped with a telescopic sight. This weapon was used by other snipers, and eventually purpose-built sniper rifles were developed specifically for this round.

In June 2017, a McMillan Tac-50 was used by a sniper with Canada's Joint Task Force 2 to kill an Islamic State insurgent in Iraq, setting the world record for the longest confirmed kill shot in military history at 3,540 meters (3,870 yd; 2.20 mi). Before that record, Canadian Army Corporal Rob Furlong of the PPCLI achieved what was then the longest-range confirmed sniper kill in history when he shot a Taliban combatant at 2,430 meters (2,660 yd; 1.51 mi) during the 2002 campaign in the Afghanistan War. This was surpassed in 2009 by a British sniper in Afghanistan with 2,475 meters (2,707 yd; 1.538 mi) using a .338 Lapua Magnum (8.58×70 mm) rifle.

In addition to long-range and anti-materiel sniping, the U.S. military uses .50 BMG weapons to detonate unexploded ordnance from a safe distance. It can disable most unarmored and lightly armored vehicles.

Some civilians use .50 caliber rifles for long-range target shooting: the US-based Fifty Caliber Shooters Association holds .50 BMG shooting matches.

Partial list of .50 BMG firearms

Carbines

• Barrett M82CQ (a carbine version of the M82A3)
• Bushmaster BA50 carbine (22" barrel version of the BA50)
• Serbu Firearms BFG-50 Carbine (22" barrel version of the BFG-50 single-shot bolt-action)

Rifles

• Accuracy International AS50
• Accuracy International AW50
• Armalite AR-50
• Arms Tech Ltd. TTR-50
• Barrett M82/M107
• Barrett M95
• Barrett M99
• Bushmaster BA50
• DSR-50
• EDM Arms Windrunner
• Gepard anti-materiel rifle
• L.A.R. Manufacturing, Inc. Grizzly Big Boar
• McMillan Tac-50
• OM 50 Nemesis
• PGM Hecate II
• Pindad SPR-2 and Pindad SPR-3
• Ramo M600
• Robar RC-50
• Serbu Firearms BFG-50 (single-shot bolt-action)
• Serbu Firearms BFG-50a (magazine fed semi-automatic )
• Serbu Firearms RN-50 (single-shot modified break-action)
• Steyr HS .50
• WKW Wilk
• Zastava M93 Black Arrow

Machine guns

• CIS 50MG
• CS/LM3 HMG
• CS/LM5 Gatling machine gun
• CS/LM6 HMG
• GAU-19
• M1921 Browning machine gun
• M2 Browning machine gun
• M85 machine gun
• MAC-58 - did not enter production
• Rolls-Royce Experimental Machine Gun - only built as prototype
• WKM-B
• W95 HMG (Type 85 HMG Export)
• XM312
• XM806 (LW50)

See also

• .50 caliber handguns
• 12 mm caliber
• 12.7×108mm
• 14.5×114mm
• List of firearms
• List of rifle cartridges
• Table of handgun and rifle cartridges
• High Explosive Incendiary/Armor Piercing Ammunition
• .510 DTC EUROP
• .510 Whisper
• NATO EPVAT testing
• Gun laws in the United States (by state)
• .50 Caliber BMG Regulation Act of 2004

External links

• .50 Caliber Browning (12.7 × 99 mm) Ammunition