Machine Gun M240

Machine Gun M240

The M240, officially the Machine Gun, 7.62 mm, M240 or unofficially the M240 Bravo, is the U.S. military designation for the FN MAG (Mitrailleuse A Gaz, “gas-operated machine gun”; alternatively, Mitrailleuse d’Appui General, “general support 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/.308 cal) 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 U.S. military are currently manufactured by FN America, the American subsidiary of FN Herstal.

The M240B and M240G are usually fired from integrated bipods, tripods, or vehicular mounts; regarding tripod use, the U.S. Army primarily uses the M192 lightweight ground mount, while the U.S. Marine Corps uses the M122A1 tripod, a slightly updated M2 tripod.

Development

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.

Variants

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 their GPMG L7s, and vice versa.

M240, M240E1, and M240C

The M240 is adapted as a 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 Corps LAV-25.

The M240E1 is the U.S. 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 cyclic rate of fire around 650–750 rounds per minute,
  • The second setting allows the weapon to have a cyclic rate of fire around 750–850 rounds per minute,
  • The third setting allows the weapon to have a cyclic rate of fire around 850–1235 rounds per minute.

M240B

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, and is also still used by some units in the US Army. 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 the “M240 Bravo” or 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 the US 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.[citation needed] 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.[citation needed] 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 to 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 US 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.

M240D

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 barrel assembly contains a three position gas regulator. The first setting allows the weapon to cycle at 650–750 rounds per minute, the second gas setting allows the weapon to cycle at 750–850 rounds per minute, and the third setting allows the weapon to cycle at 850–950 rounds per minute.

The aircraft configured M240D weighs 25.6 lb (11.6 kg) and is 42.3 in (1074.42 mm) long, whilst the egress configuration weighs 26.2 lb (11.9 kg) and is 49 in (1244.6 mm) long.

M240H

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 cyclic rate of fire of around 550–650 rounds per minute. 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.

M240N

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.

M240G

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.

M240L

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. Manufacture 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. Although the M240L has good reliability, it is still heavy for a medium machine gun.

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

Specifications

Mass
  • 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) (M240)
  • 21.7 in (550 mm) (M240B, M240G, M240L)
Width 4.7 in (120 mm)
Height 10.4 in (260 mm)

Cartridge 7.62×51mm NATO
Action Gas-operated long-stroke piston, open bolt
Rate of fire
  • M240, M240E1, M240C, M240D and M240G:
    • Gas setting 1: 650–750 rounds/min
    • Gas setting 2: 750–850 rounds/min
    • Gas setting 3: 850–950 rounds/min
  • M240B, M240L and M240H:
    • 550–650 rounds/min
  • 240LW and 240LWS:
    • 550–600 rounds/min
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)
Feed system Belt-fed using M13 disintegrating links, 50-round ammo pouch
Sights Iron sights: front blade and folding rear leaf with aperture and notch

Operators

 

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