M240 machine gun
|Machine Gun, 7.62 mm, M240|
A right-side view of the M240B
|Type||General-purpose machine gun|
|Place of origin||Belgium (designed)
United States (manufactured)
|Used by||See Users|
War in Afghanistan
Syrian Civil War
Iraqi Civil War (2014-present)
|Manufacturer||FN America, U.S. Ordnance, Barrett Firearms Manufacturing|
|Weight||27.6 lb (12.5 kg) (M240B)
25.6 lb (11.6 kg) (M240G)
22.3 lb (10.1 kg) (M240L)
|Length||49.7 in (1,260 mm)|
|Barrel length||24.8 in (630 mm)|
|Width||4.7 in (120 mm)|
|Height||10.4 in (260 mm)|
|Action||Gas-operated, open bolt|
|Rate of fire||
|Muzzle velocity||2,800 ft/s (853 m/s)|
|Effective firing range||800 m (875 yd) (bipod)
1,100 m (1,203 yd) (tripod)
|Maximum firing range||3,725 m (4,074 yd)|
|Sights||Iron sights: front blade and folding rear leaf with aperture and notch|
The M240, officially the Machine Gun, 7.62 mm, M240, is the US military designation for the FN MAG (French: Mitrailleuse d'Appui Général, English: general-purpose machine gun), a family of belt-fed, gas-operated medium machine guns that chamber the 7.62×51mm NATO cartridge.
The M240 has been used by the United States Armed Forces since the late 1970s. It is used extensively by infantry, most often in rifle companies, as well as on ground vehicles, watercraft and aircraft. Despite being heavier than some comparable weapons, it is highly regarded for reliability and its standardization among NATO members is a major advantage.
All variants are fed from disintegrating belts, and are capable of firing most types of 7.62 mm (.30 in) NATO ammunition. M240 variants can be converted to use non-disintegrating belts. There are significant differences in weight and some features among some versions which restrict interchangeability of parts. The M240s used by the US military are currently manufactured by FN America, the American subsidiary of FN Herstal.
The M240B and M240G are usually fired from an integrated bipod, a tripod, or a vehicular mount; regarding tripod use, the U.S. Army primarily uses the M192 Lightweight Ground Mount, while the U.S. Marine Corps uses the M122 tripod, a slightly updated M2 tripod.
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Manufactured by Fabrique Nationale d'Herstal, the FN MAG was chosen by the U.S. military for different roles after large worldwide searches and competitions. The MAG is a belt-fed, gas-operated, air-cooled, crew-served, fixed headspace general-purpose machine gun. Its versatility is demonstrated by its ability to be fired effectively from its integral bipod, mounted on a tripod, on ground vehicles, watercraft and aircraft.
It was first adopted by the U.S. Army in 1977, as a coaxial tank gun, and slowly adopted for more applications in the 1980s and 1990s. The M240 and M240E1 were adopted for use on vehicles. This led to further adoption in more uses, especially for the Army and Marine Corps infantry. While possessing many of the same basic characteristics as its predecessor, the durability of the MAG system results in superior reliability when compared to the M60. The MAG actually has a more complex gas system than the M60, but gives better reliability combined with lower maintenance requirements, though this comes at greater manufacturing cost and weight.
Compared to other machine guns, its rating of 26,000 mean rounds between failure (MRBF) is quite high for its weight—in the 1970s when it was first adopted it achieved about 7,000 MRBF. It is not as reliable as some very heavy older designs, but it is quite reliable for its mass.
Early history: testing and adoption
The US adoption of the MAG has its origins in the late 1960s/early 1970s as a project to procure a new coaxially mounted 7.62 mm machine gun for tanks to replace the M73 and M219 machine guns then being used. The 1950s-era M73 had been rather troubled, and the derivative M73E1/M219 was not much of an improvement. A number of designs of the period from various countries were considered; the final two candidates were the M60E2 and the FN MAG. They underwent comprehensive testing alongside the older M219 for comparison.
Two main criteria analyzed were "mean rounds between stoppages" (MRBS, malfunctions that can be cleared within minutes) and "mean rounds between failures" (MRBF, such as a part breaking). The results for the evaluated machine guns were the following:
|FN MAG 58||50,000||2962||6442|
The MAG itself underwent some improvements and the M60E2 was a specialized coaxial variant that differed from some of the other types. The qualities of the M60 variants vary considerably, such as between the M60E4 and the M60C. The clear winner was the MAG, which was designated as the M240 in 1977 after the Army competition.
The M240 was adopted as the U.S. Army's standard vehicle machine gun in 1977. The Marine Corps also adopted the M240 and M240E1 for use on vehicles like the LAV-25. It then went on to replace many older types of vehicle machine guns in the 1980s. U.S. Navy SEALs continued to use the "CAR-60" (M60E3) version of the M60 machine gun due to its lighter weight and slower rate of fire, which allows a more effective duration of fire with allowable levels of ammunition carried.
The M240 proved popular enough that it was adapted by the infantry later on, as the M240G and M240B. The USMC adopted the M240G for this role in 1991, where it not only replaced the original M60s used by the Marine Corps infantry, but also the upgraded M60E3 that the Marines had started using in the 1980s. In the late 1990s, the Army adopted the M240B for the infantry role – they had considered the M60E4, which (though lighter and cheaper) did not offer commonality with the vehicle-borne M240, other FN MAG users within NATO, or the USMC.
The various versions of the M240 have not yet entirely replaced all the M60 versions, though they have for most main applications and roles. The M60 is still, in some cases, used by the Navy.
Loading the M240 can be done either with the bolt forward or to the rear. If the bolt is to remain forward, the operator will then load the rounds into the feeding block (feed tray cover closed); or will open the feed tray cover, load the rounds onto the feeding tray, then close the feed tray cover. The charging handle will then be pulled to the rear, which locks the bolt to the rear. The weapon is then placed on safe and the charging handle is then placed back to the forward position (this is spring-loaded on the tank-mounted variation). The weapon is now ready for operation.
The weapon fires from the open bolt position, meaning that the bolt is held to the rear and only moves forward as it is firing a round. The firing pin is static and the bolt moves around the firing pin, circumventing any need for a hammer. A sear is used to time the internal mechanisms of the weapon to provide a consistent rate of fire, ensuring proper function and accuracy. However, firing from an open bolt also provides the possibility of an accidental discharge due to a bolt override. This happens when there is enough force for the bolt to jump over the sear and fire without the trigger being pulled. The safety on the weapon cannot stop this from happening. The safest way to protect against this is to leave the bolt forward on the weapon until the operator is ready to fire the weapon; then charge the weapon and fire.
Clearing the weapon is performed by ensuring that the bolt is locked to the rear and the weapon is on safe. The top cover is then lifted, the remaining belt (if any) is swept out of the feed tray, the feed tray is lifted to visually inspect the chamber and the face of the bolt. Any links or brass casings are removed. The weapon is now clear. In the extremely unlikely event that a live round is on the bolt face, it is knocked loose with a cleaning rod or another rigid object. If there is a live round lodged in the barrel, the operator must immediately decide if the barrel is hot enough that there is a chance of it cooking off. If there is, he will immediately move his face away from the opening of the weapon; and aiming the gun in a direction that is perceived to take the least amount of damage and/or casualties should the event of a cook-off occur. He should then wait for the barrel to cool off before attempting to remove it. He can also attempt to extract the round by closing the cover, taking the weapon off of safe, and pulling the trigger. This will likely causing the weapon to fire, so care should be made in ensuring that the weapon is first pointed in a safe direction.
The rate of fire may be controlled by three different gas regulator settings. The first setting allows the weapon to cycle at 650–750 rounds per minute, the second setting being 750–850 rounds per minute, and the third setting being 850–950 rounds per minute. These settings are changed by dismounting the barrel, removing the gas regulator collar and turning the gas regulator to allow more or less gas to move through the weapon system. It is generally performed only when necessary to return the gun to operation after fouling has caused sluggish operation and there is no time to properly clean the weapon.
The barrels can be exchanged rapidly, thanks to a barrel release button located on the left side of the weapon. The weapon is cleared first and then the button is held down, while the barrel's carrying handle is moved from the right side of the weapon to the center, unlocking it from the receiver. At this point, the button is released and the barrel is then pulled free of the receiver and placed to the side. The new barrel is inserted into the receiver and then the carrying handle is shifted to the right, locking it into place. Headspace is set by counting the clicks as the barrel is locked down and should be between two and seven clicks.
During prolonged firing, care must be taken to not allow exposed skin to come in contact with the weapon. The barrels can become hot enough to inflict second-degree burns instantly without becoming visibly different. These hot barrels glow brightly to anyone using any sort of optics sensitive to infrared radiation, such as night vision devices.
The manufacturer's name for the weapon is the MAG 58. The M240 adheres to FN MAG-58 specifications, allowing parts to be interchanged with other standard MAG-58s. This has significant advantages in training, logistics support, tactical versatility, and joint operations. For example, a US unit with attached British troops could supply replacement parts for the L7s, and vice versa.
M240, M240E1, and M240C
The M240 is designed as coaxial machine gun for tanks and 7.62 mm fire power on light armored vehicles. The M240 is part of the secondary armament on the U.S. Army M1 series Abrams tank, M2/M3 series Bradley Fighting Vehicle, and the U.S. Marine Corp LAV-25.
The M240E1 is the US Marine Corps version of the original M240 coaxial/pintle-mounted machine gun, that is used on vehicles, like the LAV-25. It can also be fitted with spade grips for flexible use, like the ones from the M240D.
The M240C is the right hand variant on the original coaxial (installed alongside the main weapon) M240, it is identical to the M240 except for the ammunition cover and feed tray. It has a right-handed feed for use on the M2/M3 Bradley Fighting Vehicle and LAV as the coaxial machine gun. It is fed from the left on the M1 Abrams and other M1 variant (M1A1, M1A2, M1A2 SEP) tanks. The M240C uses a charging cable instead of a charging handle, has a cut-off pistol grip and has a special paddle assembly that allows the trigger to be actuated by means of a solenoid. Since the machine gun is not meant to be handled during use, the barrel is fully exposed and must be handled with asbestos mittens during barrel changes.
The rate of fire of the M240, M240E1, and M240C can be controlled by three different gas regulator settings;
- The first setting allows the weapon to have a fire rate of 650–750 rounds per minute.
- The second setting allows the weapon to have a fire rate of 750–850 rounds per minute.
- The third setting allows the weapon to have a fire rate of 850–950 rounds per minute.
The M240B (formerly called as the M240E4) is the standard infantry medium machine gun of the U.S. Marine Corps. The US Navy and Coast Guard likewise utilize the weapon system. It is also still used by some Army units. It comes configured for ground combat with a buttstock and bipod, though it can also be mounted on tripod, ground vehicles, aircraft, aboard ships and small boats. It is almost always referred to as an "M240 Bravo" or even just "240" verbally. The M60E4 (Mk 43 as designated by the U.S. Navy) was pitted against the M240E4 (former designation of the M240B) in Army trials during the 1990s for a new infantry medium machine gun, in a competition to replace the decades-old M60s. The M240E4 won, and was then classified as the M240B. This led to 1,000 existing M240s being sent to FN for an overhaul and a special kit that modified them for use on ground (such as a stock, a rail, etc.). This led to procurement contracts in the late 1990s for the all-new M240B. However, a new feature was added, a hydraulic buffer system to reduce the felt recoil as incorporated in the M60. While the M240B had been more reliable in the tests, it was a few pounds heavier than the M60E4, which led to the development of the lighter M240L machine gun. The Army M240 converted to the M240B configuration should not be confused with the large numbers of M240/E1 converted to the M240G configuration for the Marine Corps.
In the Marine Corps, the M240G is the predecessor of the M240B. The main differences between the two machine-gun variations is the picatinny rail system, hydraulic buffer inside of the butt stock to reduce the amount of recoil felt by the gunner, and the number of gas settings on the gas regulator plug. The M240G has three gas settings, allowing the machine gun to have a fire rate between 650–950 rounds per minute depending on the setting selected, whereas the M240B only has one setting, restricting the fire rate between 550–650 rounds per minute. The smaller gas port used on the M240B slows down the rate of fire, which increases the longevity of the machine-gun by reducing stresses on the action. A side effect is a weapon that will not fire when extremely dirty as the energy on the piston is reduced. The Marine Corps relies on fire discipline among its machine gunners to not set it to the largest port unless required.
The M240B is being tested with a new adjustable buttstock that may replace the current stock of the M240B. The lighter M240L has started to replace the M240B in U.S. Army service. The Marine Corps is observing the progress of the M240L, but feels it is too expensive for adoption. The Corps is instead looking to upgrade the M240 barrel through several ways, including carbon fiber coatings, new alloys, or ceramic liners, to lighten and strengthen the barrel. The goal would be a barrel that would not need to be changed, would weigh the same, but decrease heat retention, lessen warping, and eliminate cook-offs. They are also interested in incorporating a suppressor into the barrel, rather than having to attach one, to reduce the sound of shots and make it difficult to determine where the gunner is located.
The M240D is an upgrade of the M240E1, primarily in the addition of an optical rail on the receiver cover. It has two possible configurations: aircraft and egress (ground). In the aircraft configuration, the M240D has a front and rear sight and a trigger group which accommodates the spade grip device, while the ground configuration involves the installation of an Egress Package or "infantry modification kit", which is designed to provide downed aircrew personnel with increased firepower. The Egress Package contains a buttstock assembly, a buffer assembly, a bipod assembly, and a conventional trigger assembly.
The M240D is issued for aircraft configuration. The barrel assembly contains a three position gas plug. The first gas plug position allows the weapon to cycle at 650–750 rounds per minute (RPM), the second gas plug positions allows the weapon to fire at 750–850 rounds per minute (RPM), and the third gas plug position allows the weapon to fire at 850–950 rounds per minute (RPM). The aircraft configured M240D weighs 25.6 lb (11.6 kg) and is 42.3 in (1074.42 mm) long, while the egress configuration weighs 26.2 lb (11.9 kg) and is 49 in (1244.6 mm) long.
The M240H (formerly designated as the M240E5) is an improvement of the M240D, the M240H features a rail-equipped feed cover, an improved flash suppressor, and has been configured so that it can be more quickly converted to infantry standard using an Egress Kit. The M240H has an overall length of 41.6 in (1056.6 mm) with a 21.7 in (551.2 mm) barrel and weighs 26.3 pounds (11.9 kg) empty, and has a rate of fire of 550–650 rounds per minute (RPM). The M240H entered service in 2004 on U.S. Army helicopters. It is equipped with dual spade grips and thumb-activated trigger systems, and can be quickly converted for dismounted infantry use via an egress components kit that includes a bipod and conventional pistol grip trigger module.
The M240N is designed with a front and rear sights, and configured specifically for mounting on water craft. It is similar to the M240G, but lacks the integral bipod. It also uses the hydraulic buffer of the M240B, and features the lower cyclic rate of fire of the M240B which is around 550–650 rounds per minute (RPM).
The M240G allows for commonality throughout the Marine Corps whether the weapon is used in an infantry, vehicular, or airborne role. The M240G is the ground version of the original M240 or M240E1, 7.62 mm medium class weapon designed as a coaxial/pintle-mounted machine gun for tanks and LAVs. The M240G can be modified for ground use by the installation of an "infantry modification kit" (a flash suppressor, front sight, carrying handle for the barrel, a buttstock, infantry length pistol grip, bipod, and rear sight assembly). The M240G lacks a front heat guard, and as such is a few pounds lighter than the M240B, weighing in at 25.6 pounds (11.6 kg). The rate of fire of the M240G can be controlled by three gas settings. On gas setting one the weapon will fire at 650–750 rounds per minute, on gas setting two the weapon will fire at 750–850 rounds per minute, and on gas setting three the weapon will fire at 850–950 rounds per minute. The size of the gas port increases resulting in greater energy being delivered to the action. Use at high settings induces added stresses on the action and results in a shorter service life of the weapon. It gives the operator an ability to adjust the gas bleed to the action. This also allows the weapon to continue firing when very dirty from sustained use in combat conditions when it may be otherwise rendered inoperable due to an extremely dirty and dry action.
The M240L (M240 Lima), formerly the M240E6 is the product of the M240B Weight Reduction Program which reduces the weight of the existing M240B by 5.5 pounds (2.5 kg). To achieve 18% weight savings, the M240L incorporates titanium construction and alternative manufacturing methods for fabricating major components. The resulting improvements reduced the soldier's combat load while allowing easier handling and movement of the weapon. The M240L may replace the M240B in U.S. Army service. It was type classified in the fourth quarter of fiscal year 2010.
Titanium was used to make the receiver body, front sight post, and carrying handle while maintaining steel operating system components. The manufacturing process had to be adjusted because titanium takes longer to machine than steel and requires more frequent replacement of tooling bits; more pliable stainless steel rivets were used, and the receiver was coated with boron and chrome carbo-nitride coatings with a ceramic-based top coat to preserve it under extreme operating temperatures. The M240L weighs 22.3 lb (10.1 kg) with a standard-length barrel and standard stock, and weighs 21.8 lb (9.9 kg) with a shorter barrel and collapsible stock. The short barrel is 4 in (100 mm) shorter than a standard M240 barrel, and with the collapsible stock the M240L can be made 7 in (180 mm) shorter. The smaller and lighter variant of the M240L is the M240P, which is still in a testing phase in Afghanistan. The M240P is not used as often as its predecessors. The Army initially bought 4,500 M240Ls, and plans to buy 12,000 total.
M240L 7.62 mm medium machine gun (Light) specifications:
- Operation: Gas-operated (full-auto)
- Feed System: NATO standard disintegrating link belt-fed
- Length: 1,230 mm (48.5 in) with the standard barrel and 1,130 mm (44.5 in) with the short barrel
- Barrel Length: 551.18 mm (21.7 inch)
- Weight: 10.1 kg (22.3 lb)
- Caliber: 7.62 mm (7.62×51mm NATO)
- Maximum effective range: 1,100 meters with tripod and T&E (the latest FM reads 1,800 m)
- Maximum range: 3,725 meters
- Tracer burnout: 900 meters
- Cyclic rate of fire (hydraulic buffer): 550–650 rounds per minute
The M240L mounted on the M192 Lightweight Ground Mount.
The M240D machine gun is fired from a SH-60F Sea Hawk.
- Georgia: Being introduced for the Georgian Army. To become standard issue GPMG.
- Spain: Used by the Spanish Army Airmobile Force.
- United States: Standard to all units of the U.S. Army, also used by U.S. Air Force Security Forces.
- Philippines: Used by the Philippine National Police-Special Action Force.
- M60 machine gun (7.62×51mm machine gun)
- M249 light machine gun (5.56×45mm machine gun)
- Mk 48 machine gun (M249-derived 7.62×51mm machine gun)
- IWI NEGEV (Israeli 5.56×45mm machine gun)
- IWI NEGEV NG-7 (7.62×51mm machine gun variant of the NEGEV)
- PK machine gun (Soviet 7.62×54mmR machine gun)
- UKM-2000 (Polish PK-derived 7.62×51mm machine gun)
- CETME Ameli (Spanish 5.56×45mm machine gun)
- Rheinmetall MG 3 (German 7.62×51mm machine gun)
- List of firearms
- List of weapons of the United States Marine Corps
- List of individual weapons of the U.S. Armed Forces
- List of crew-served weapons of the U.S. Armed Forces
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|Wikimedia Commons has media related to M-240 machine gun.|
- Official list of FN Military Machine Gun
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- Chapter 3, M240B Machine Gun, Field Manual 3–22.68, Crew-Served Machine Guns, 5.56 mm and 7.62 mm, Department of the Army, 31 January 2003
- Federation of American Scientists: M240
- M240 Gun Fact Files, US Army
- Original test report of multiple machine guns, including the later M240 (as MAG58)
- Video #1 of the M240