M240
Encyclopedia : M : M2 : M24 : M240
| ||
| M240B pictured | ||
| Caliber: | 7.62 × 51 mm NATO | |
| Firearm action: | Gas-operated, open bolt | |
| Designed by: | Derived from the FN MAG | |
| Belt: | 100 or 200-round disintegrating links | |
| Overall length: | 1,245 mm (49 in) | |
| Barrel length: | 627 mm (24.68 in) | |
| Effective range: | 1,800 m (1,970 yards) | |
| Maximum range: | 3,725 m (4,073 yards) | |
| Rate of fire: | 650–950 round/min | |
| Maximum ROF: | 200 round/min | |
| Sustained ROF: | 100 round/min | |
| Muzzle velocity: | 2,970 ft/s (905 m/s) | |
| Weight: | 12.5 kg (27.6 lb) | |
| Production (MAG): | 1958— | |
The M240 designation is used to describe the whole family, but it is also a specic variant- a specialized co-axial model. There are many versions in service, see selected versions below:
- M240- a co-axial version adopted in 1977 by the US Army for use in tanks. This version of the FN MAG beat out the M60E2 and M219, as well as host of other medium machine guns including the MG3 and AA-52 co-axial versions. Entered service in the 1980s on the M1 Abrams.
- M240E1- a pintle mounted version that also entered service in the 1980s. Also used by USMC.
- M240G- a version used by the USMC starting 1994, including in infantry configuration as opposed to the previous vehicle mounted types.
- M240B- a ground version adopted by the Army in the late 1990s, with deliverys starting around 1998. Includes recoil buffer and front heat guard. Beat out other medium MGs.
- M240H- an improved model mainly for aircraft developed in the early first decade of the 2000s.
The M240B/G are usually fired with a bipod, M122A1 tripod, or from various pintle mounts.
History and design
Manufactured by Fabrique Nationale's subsidiary FN Manufacturing, Inc. Columbia, SC, the M240 (FN MAG) was chosen by the U.S. military for different roles after large world-wide searches and competitions. It has mainly replaced the venerable M60 in most roles, though it replaced some other mgs in the co-axial. M60s have remained in use, but they are being slowly phased out and replaced by the newer M240s as they wear out.
The M240 is a belt-fed, gas-operated, air-cooled, crew-served, fixed head space weapon. Its functionality is demonstrated by its ability to be mounted on the M122A1 tripod, a bipod, on vehicles, or on aircraft. The M60 is still used as a door gun on Army helicopters, however.
It was first adopted in 1977 by the U.S. Army as a co-axial tank gun, and slowly adopted for more applications in 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 infantry. While possessing many of the same basic characteristics as its predecessor, the durability of the M240 system results in superior reliability and maintainability when compared to the M60. The M240 actually has a more complex gas system than M60s, but can function better with less maintenance and has higher reliabilty.
Compared to other machine guns, its rating of 26,000 Mean Rounds Between Failure (MRBF) is quite high for its weight. It is not as reliable as some very heavy older designs, but it is for its mass.
They are both (M60/M240) scheduled to be replaced by a lightweight machine gun (JSSAP/PMSW), which will also replace some of the M249s. Among the likely candidates is another FN product, SOCOM's latest 7.62 mm machine gun — the M249-derived Mk 48 Mod 0 —, scheduled for fielding starting in 2006 with special operations units.
Early history: testing and adoption
The adoption of the M240 has its origins in the late 1960s/early 1970s as a project to procure a new vehicle-mounted co-axial 7.62 mm machine gun (as well as a replacement for the M85 .50 caliber machine gun being used as a tank coaxial. It would go on to be deployed in this role in the 1980s, but spawn its adoption for the infantry and other mountings as well. It would be deployed in this, and some other roles into the 1990s and 2000s.As mentioned, during the 1970s the Army was looking for new 7.62 mm machine guns for vehicle/AFV mounts. The 1950s-era M73 had been rather troubled, and the M73E1/M219 it was developed into was not much of an improvement. A number of designs of period from various countries were considered, but it was narrowed down to the M60E2 and the FN MAG. They underwent a large testing, including the older M219 as well.
Two main criteria analyzed were "Mean Rounds Between Stoppages" (MRBS, jams that can be cleared within minutes) and "Mean Rounds Between Failures" (MRBF, such as a parts breaking). The results for the evaluated machine guns were the following:
Type Rounds Fired MRBS MRBF FN MAG 58 50,000 2,962 6,442 M60E2 50,000 846 1,669 M219 19,000 215 1,090 Minimum specified 850 2,675 Minimum desired 1,750 5,500The test applies only to the 70s-era versions tested. The M240 itself underwent some improvements and the M60E2 was a specialized co-axial 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.
That aside, for these types the clear winner was the MAG, which was designated as the M240 in 1977 after the Army competition. It went on to replace many older types for the vehicle/co-axial role in the 1980s. The M240 proved popular enough that it would be adapted by the infantry later on, spawning the M240B and M240G. It was adopted for this role in 1991 by the Army, replacing the rather worn M60s used by infantry, but also the M60E3 that the Marines had started using in the 1980s. The various versions of the M240 never entirely replaced all the M60 versions, though it did for most main applications and roles.
Variants
The NATO version of the M240 is known as the MAG 58. The U.S.-made M240 family is produced under the same specifications as the MAG 58, enabling all M240 variants to have interchangeable/interoperable components with foreign-produced NATO equivalent weapons. This has significant advantages in training, logistics support, tactical versatility, and joint operations. For example, an M240B's buttstock and bipod may be carried in a vehicle to enable the crew to convert the coaxial weapon to an infantry model in the event that they are forced to withdraw from a non-operable vehicle.
M240
This was adopted in 1977 by the Army to replace the M73 and M219 7.62 mm machine guns, and the M85 .50 cal. In the 1980s, the Marines adopted the M240 and M240E1 for use on vehicles like the LAV-25. The M240C is similar, for co-axial/vehicle mounting.M240E4/M240B
The M240B is the standard infantry medium Machine gun of the U.S. Army. It comes configured for ground combat. It is sometimes referred to as a "240 Bravo".The M60E4 (Mk 43 as designated by the U.S. Navy) was pitted against the (then called) M240E4 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 1000 existing M240 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 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, and there is program underway for a new lightweight medium machine gun in the early 2000s. The Army M240 converted the M240B configuration should not be confused with the large numbers of M240/E1 converted to the M240G configuration for the Marine Corps.
M240C
The M240C is a variation on the original co-axial M240, but with a right-handed feed.
M240E1 and M240D
The M240D has two possible configurations: aircraft and egress (ground). The aircraft configured M240D has a front and rear sight and a trigger group which accommodates the spade grip device. The ground configuration involves the installation of an Egress Package or "infantry modification kit" which is designed to provide downed aircrew personnel with increased fire power. The M240D is an upgrade of the M240E1, primarily in the addition of an optical rail on the receiver cover. The M240E1 had also fitted with spade grips for flexible use.M240G
A similar version of the M240, the M240G (referred to as the "240 Golf"), is the standard U.S. Marine Corps medium machine gun. The Marine Corps has replaced the M60E3 with the M240G. The M240 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 240G lacks a front heat guard, and is few pounds lighter at 25.6 pounds, than the M240B.- Manufacturer: Fabrique Nationale Manufacturing, Inc.
- Length: 49 in (124.46 cm)
- Weight: 25.6 lb (11.61 kg)
- Bore diameter: 7.62 mm (.308 in)
- Maximum effective range: 1,800 m (1,970 yards) on tripod mount
- Maximum range: 3,725 m (4,073 yards)
- Rate of fire:
- *Cyclic: 650–950 rounds per minute (adjustable)
- *Rapid: 200 rounds per minute
- *Sustained: 100 rounds per minute
- Unit replacement cost: $6,600
M240E5/M240H
An improvement of the M240D, the M240H (sometimes referred to as the "240 Hotel") 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.M240E6
The E6 is currently in testing, and is a basic infantry model designed to rectify one of the M240's few short-comings: weight. The E6 is a lightweight model making use of a titanium receiver block.Operation
Loading the weapon is performed by pulling the charging handle to the rear, locking the bolt to the rear, placing the weapon on safe and then pushing the charging handle forwards. The feed tray cover is then lifted and rounds are laid inside the feed tray. The feed tray cover is then closed and the weapon is ready for operation.Clearing the weapon is performed by ensuring the bolt is locked to the rear and the weapon is on safe. The feed tray 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 rear of the barrel and the face of the bolt. Any links or brass casings are removed. The weapon is now clear. In the 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. He should then wait for the barrel to cool off before attempting to remove it. In many cases, attempting to remove the barrel will cause the round to detonate as soon as the barrel is unlocked from the receiver. He can also attempt to extract the round by taking the weapon off of safe, pulling the trigger and pulling back on the charging handle. This has a fair chance of causing the weapon to fire, so care should be made in ensuring that the weapon is pointed in a safe direction first.
The rate of fire may be controlled by three different settings. The first setting allows the weapon to cycle at 750 round/min. The two remaining settings increase the rate of fire by 100 round/min per setting — second setting being 850 round/min and third setting, 950 round/min). 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 before missions, as changing the setting is distracting at best under field or combat conditions.
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.
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. However, such barrels glow brightly to anyone using any sort of night-vision device.
Lessons learned report
An April 2002 presentation by the Natick Soldier Center reported on lessons learned from M240B use in Afghanistan (such as used during Operation Anaconda):M240B Machine Gun Lessons Learned
- 17% reported engaging the enemy with their M240B;
- 42% reported problems getting spare parts in Afghanistan (barrels, springs, small roll pins, T&E pin, heat shields, sear pins, spare barrel bag, cleaning materials);
- 1 soldier reported a double feed in combat;
- 50% reported that they need better ways to carry ammunition (ammo bag, etc);
- 100% were confident in their weapon;
- 82% felt that their M240B was reliable;
- Suggestions: improved sling, lighter, more durable tripod, more durable heat shield.
See also
- M249 (5.56 mm machine gun)
- M60 (7.62 mm machine gun)
- Mk 48 Mod 0 (M249-derived 7.62 mm machine gun)
- List of firearms
- List of modern weapons
- List of weapons of the U.S. Marine Corps
- List of individual weapons of the U.S. Armed Forces
- List of crew-served weapons of the U.S. Armed Forces
External links
- [Federation of American Scientists: M240]
- [USMC Factfile: M240G]
- [Fabrique Nationale Product Page]
- [DTIC.mil PowerPoint Slides on Small Arms development] (needs PPT viewer)
- [Nazarian`s Gun`s Recognition Guide]
- [About safety with M240 and 249]
From Wikipedia, the Free Encyclopedia. Original article here. Support Wikipedia by contributing or donating.
All text is available under the terms of the GNU Free Documentation License See Wikipedia Copyrights for details.