Military :General Purpose Machine Gun

The MAG is a Belgian 7.62 mm general purpose machine gun, designed in the early 1950s at Fabrique Nationale (FN) by Ernest Vervier. It is used by almost 70 countries, in 25 of those countries it is a standard-issue support weapon, it was produced locally in 7 countries (Argentina, Egypt, India, Singapore, Taiwan, USA and the United Kingdom). The weapon’s name is an abbreviation for Mitrailleuse d`Appui Général[1] – "general purpose machine gun" (GPMG). The MAG is available in three primary versions: the standard, heavy infantry Model 60-20 machine gun, the Model 60-40 coaxial machine gun for armoured fighting vehicles and the Model 60-30 aircraft variant.

Design details

A U.S. Marine firing the British L7A2 version of the MAG.The MAG Model 60-20 is an automatic, air-cooled, gas-operated weapon that uses ignited powder gases vented through a port in the barrel to propel a gas piston rod connected to the locking assembly (it uses a short-stroke piston system). The barrel breech is locked with a vertically-tilting, downward locking lever mechanism that is connected to the bolt carrier through an articulated joint. The locking shoulder and camming surfaces that guide the locking lever are located at the base of the receiver. The MAG uses a series of proven design concepts from other successful firearms, for example the locking mechanism is modeled on that of the Browning M1918 (BAR) automatic rifle, and the feed and trigger mechanisms are from the WWII-era MG42 universal machine gun.

The MAG fires from an open bolt. Both the spring-powered extractor and ejector are contained in the bolt. After firing, spent cartridge casings are removed through an ejection port located at the base of the receiver (a spring-loaded dust cover of the MG42 type covers the ejection port). The machine gun has a striker firing mechanism (the bolt carrier acts as the striker as it contains a channel that houses the firing pin, which protrudes out from the surface of the bolt upon firing), an automatic-only trigger assembly and a manual cross-bolt push-button safety, which is located above the pistol grip. With the safety placed in the “safe” setting, the sear mechanism is disabled. The safety can only be engaged with the weapon cocked.

The weapon feeds from the left-hand side from open-link, metal ammunition belts: either the American disintegrating M13 belt (NATO standard) or the segmented German DM1 belt, whose 50-round sections can be linked together through a cartridge. In order to adapt the weapon to feed from one belt type to the other, several components of the feed mechanism need to be reconfigured since the position of the feed tray's cartridge stop and pawl angles in the top cover are different. The MAG features a pawl-type feeding mechanism that continues to move the feed link during both the rearward and forward cycles of the reciprocating bolt carrier, producing a smooth belt flow. The feeding mechanism’s three pawls are actuated by a roller connected to the bolt carrier. The feed channel rail, feed link, both feed slides and the feed tray are chrome plated. The top cover body is an anodized aluminum casting. In the infantry assault role, the weapon can be fitted with a sheet metal container that houses a 50-round belt and is attached to the left side of the receiver.

The quick-change barrel has a slotted flash suppressor. The barrel’s chamber and bore are chromium-lined and the barrel has 4 right-hand grooves with a 305 mm (1:12 in) rifling twist rate. Also attached to the barrel is the front sight base, carry handle and gas block (equipped with an exhaust-type gas regulator valve with three settings).

The machine gun is fitted with a folding bipod (attached to the end of the gas cylinder) that cannot be adjusted for height. The aluminum legs can be folded back for carrying or use as a forearm — and secured in slots under the receiver by their hooks and a spring-loaded catch. When firing from the hip, the bipod legs remain extended and the left leg is gripped for support. The bipod can be removed from the gas cylinder by tapping-out a roll pin in the gas cylinder head until it's flush and the bipod can be rotated enough to clear the gas cylinder's retaining lugs. The MAG is also equipped with a fixed wooden stock, pistol grip, carrying handle and iron sights that consist of a forward blade (adjustable mechanically for both windage and elevation) and a folding leaf rear sight with an aperture in the down position for firing distances from 200 to 800 m in 100 m increments and an open U-notch for ranges from 800 to 1,800 m graduated every 100 m. The rear sight is hinged to a base with protective ears that is integral with the receiver's upper forging.

The MAG’s receiver is constructed from sheet metal stampings reinforced by steel plates and rivets. The front is reinforced to accept the barrel nut and gas cylinder which are permanently mounted. Guide rails that support the bolt assembly and piston extension during their reciprocating movement are riveted to the side plates. The bolt's guide rails are shaped downward to drive the locking lever into engagement with the locking shoulder — also riveted to the side plates. The rear of the receiver has been reinforced and slotted to accept the butt-stock.
In the static machine gun role the weapon is mounted on a tripod that offers a higher degree of accuracy and control than the bipod, for example the FN 360° tripod, which features an elevation adjustment mechanism that enables the weapon’s bore axis to be maintained from 300 mm (11.8 in) to 600 mm (23.6 in), has a -30° to +15° elevation change and a 360° traverse range.

The vehicle-mounted variant of the MAG lacks a stock, bipod, carry handle, pistol grip and ejection port dust cover, it does however have a new closed-type gas regulator. Depending on the weapon’s employment, the machine gun can also be fitted with an extended charging handle linkage, standard trigger group (with a pistol grip), or a specialized trigger assembly with an electrically-fired trigger.
The pintle-mounted aircraft model is fed from either the right- or left-hand side exclusively with the M13 belt. Thus configured weapons typically lack standard iron sights and are equipped with electrically powered triggers.
The MAG fires the 7.62x51mm NATO cartridge. A variant was also produced for the Swedish Army (designated the Ksp 58), that was adapted to use the 6.5x55mm Mauser rifle cartridge.