FN MAG

The FN MAG is a Belgian 7.62 mm general-purpose machine gun, designed in the early 1950s at Fabrique Nationale by Ernest Vervier. It has been used by more than 80 countries and it has been made under licence in several countries, including Argentina, Canada, Egypt, India, and the United Kingdom.
The MAG is available in three primary versions: the standard, infantry Model 60-20 machine gun, the Model 60-40 coaxial machine gun for armoured fighting vehicles, and the Model 60-30 aircraft variant.

History

After World War II the Swedish Army, who used two 6.5×55mm versions of the Browning Automatic Rifle since the 1920s, wanted to replace them with a belt-fed version. FFV-Carl Gustaf tried to design a derivative, but their belt feeding mechanism did not pass military trials. Therefore FN Herstal was approached, and Belgian designers came up with the idea to flip the BAR action upside down and mate it with the proven MG 42 belt-feeding mechanism. The work was started in the late 1940s by Dieudonné Saive and finished by Ernest Vervier in 1953, with Swedish trials beginning in 1955.
The MAG served as a complement to the FN FAL battle rifle. It first entered production in 1958, and it is sometimes referred to as the MAG-58.

Design details

The MAG Model 60-20 is an automatic, air-cooled, gas-operated machine gun, firing belt-fed 7.62×51mm NATO from an open bolt. 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 automatic rifle, which FN produced under license with some adaptions, and the feed and trigger mechanisms are from the WW II-era MG 42 universal machine gun.

Operating mechanism

The MAG operates via a long-stroke piston system, which utilizes the ignited powder gases generated by firing vented through a port in the barrel to propel a gas piston rod connected to the locking assembly. 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 unlocking sequence starts after rearward gas piston rod movement to keep the breech block fully locked until the bullet has left the gun barrel and the high-pressure propellant gas pressure has dropped to a safe level.
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 downwards through an ejection port normally covered by a spring-loaded dust cover at the bottom of the receiver. The machine gun has a striker firing mechanism, an automatic-only trigger assembly and a manual cross-bolt push-button safety, which is located above the pistol grip.

Features

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, which is also riveted to the side plates. The rear of the receiver has been reinforced and slotted to accept the butt stock. The MAG is also equipped with a fixed wooden stock, pistol grip, and carrying handle.
A user-adjustable gas valve allows regulating the cyclic rate of fire from 650 up to 1,000 rounds per minute, and subsidiary can adjust the gas system for various types of cartridge loadings or use in the presence of heavy fouling. A high cyclic rate of fire is advantageous for use against targets that are exposed to a general-purpose machine gun for a limited time span, like aircraft or targets that minimize their exposure time by quickly moving from cover to cover. For targets that can be fired on by a general-purpose machine gun for longer periods than just a few seconds, the cyclic firing rate becomes less important.

Barrel

The quick-change barrel has a slotted flash suppressor. The barrel's chamber and bore are chrome-lined or stellite-lined for increased service life and the barrel has four right-hand grooves with a 305 mm rifling twist rate. Also attached to the barrel is the front sight base, carry handle and gas block. The barrel assembly weighs and of the long barrel a portion of is rifled. The MAG takes zero shifts between barrel assemblies into account by making the front sight of the assemblies adjustable with the help of tools.

Feeding

The weapon feeds from the left side from open-link, metal ammunition belts: either the American disintegrating M13 linked belt or the non-disintegrating segmented German DM1 belt, whose 50-round sections can be linked through a cartridge. The DM1 belt is based on the last version of the Gurt 34/41-family used in World War II in MG 34 and MG 42 machine guns. After firing, the separated M13 link or emptied DM1 belt section is cleared out on the right side of the receiver through an ejection port normally covered by a spring-loaded dust cover.
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.

Sights

The MAG is equipped with iron sights that consist of a forward blade and a folding leaf rear sight with an aperture in the down position for firing distances from in increments and an open U-notch for ranges from graduated every. The rear sight is hinged to a base with protective ears that is integral with the receiver's upper forging. The iron sight line has a sight radius.
The top of later production model receivers often feature a MIL-STD-1913 rail as a mounting platform for firearm accessories like optical sights and night-vision devices.

Safety

With the safety placed in the safe setting, the sear mechanism is disabled. The safety can only be engaged with the weapon cocked.

Bipod and tripod

For the light machine gun fire support role, the gun is fitted with a folding bipod that can be adjusted for height. For carrying or use as a forearm, the aluminum legs can be folded back and secured in slots under the receiver by 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 is flush and the bipod can be rotated enough to clear the gas cylinder's retaining lugs.
In the static medium machine gun sustained fire support 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 to, has a 30° to +15° elevation change and a 360° traverse range.

Variants

Variants of the FN MAG were manufactured by at least ten companies: FN Herstal, Fabricaciones Militares, Changfeng Machinery, Indian Ordnance Factories, Carl Gustaf Stads Gevärfaktori, the Ordnance Development and Engineering Company of Singapore, Canadian Arsenals Limited, the Royal Small Arms Factory, Heckler and Koch, U.S. Ordnance, Barrett Firearms Manufacturing, Manroy Engineering, Yunnan Xiyi Industry Company Limited, and Egypt's Maadi Company for Engineering Industries.

FN production variants

Designation	Description
MAG 60.20	Standard infantry version with pistol grip, fixed buttstock and bipod; Many subvariants including the T3 and T6
MAG 60.30	Fixed aircraft version, firing from a solenoid trigger; Capable, at least in some subvariants, of left and right hand feeding
MAG 60.40	Coaxial version for armoured fighting vehicles; Many subvariants including the T3
MAG 10.10	Jungle version with shorter barrel and buttstock.

The vehicle-mounted variant of the MAG lacks a stock, bipod, carry handle, pistol grip, ejection port dust cover and a mount for optical sights. 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, 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.

British versions

The L7 general-purpose machine gun was adopted by the British Armed Forces as a replacement for the long-serving Vickers machine gun and the Bren, following trials in 1957. Originally made under license from FN by the Royal Small Arms Factory at Enfield Lock from 1961 until the site's closure in 1988, the L7 and its variants were later produced by Manroy Engineering,, and are currently produced by Heckler & Koch. The series remains in active service with all components of the British Armed Forces. There have been two main variants, the L7A1 and L7A2, developed for infantry use, with the L7A2 having superseded the earlier variant. Several other variants have been developed, notably the L8, modified for mounting inside armoured vehicles. Although intended to replace the Bren entirely, that light machine gun continued in use in jungle terrain, where there was no requirement for the medium machine gun role, and with secondary units, until the adoption of the L86A1 Light Support Weapon. The LSW was intended to replace both the L7 and the L4 in the light machine gun role, but dissatisfaction with the L86's sustained fire capabilities and reliability resulted in combat units continuing to utilize the L7 whenever possible. The British Army, Royal Marines and RAF Regiment were issued with the L110A2 to replace the LSW as the light section support or fire support weapon. This uses the same NATO-standard 5.56×45mm ammunition as the L85 assault rifle. However a review of requirements led to the withdrawal of both the L110A2 LMG and L86A2 LSW from service in 2018, with the 7.62 mm L7A2 resuming its place in the British Army infantry section. Other variants continue to be used in mounted roles on many British military vehicles, naval vessels and aircraft.
In 1961, the Royal Small Arms Factory, Enfield in the United Kingdom, undertook licence production of the MAG in the following versions: L7A2, L8A2, L37A2, L20A1 and the L43A1. These models all use the M13 ammunition belt.
The L7A2, general-purpose machine gun, replaced the L7A1 in service with the British Army. Compared to the MAG Model 60-20, it features, among other minor changes, an improved feed mechanism, a 10-position gas regulator valve, a polymer butt-stock, a provision for 50 round belt-box and a bracket, used to mount optical day- and night-vision sights, mounted to the left side of the receiver. In the sustained fire role, the L7A2 can be mounted on the L4A1 tripod in conjunction with a C2A2 Support Weapons Sight or the sight unit used on the FGM-148 Javelin anti-tank missile system. Fired by a two-man team who are grouped in a specialist Machine Gun Platoon the L7A2 in conjunction with a C2A2 Support Weapons Sight can provide battalion-level direct support fire at ranges up to and indirect map and range table predicted support/harassment fire out to. The indirect firing method exploits the 7.62×51mm NATO useful maximum range, that is defined by the maximum range of a small-arms projectile while still maintaining the minimum kinetic energy required to put unprotected personnel out of action, which is generally believed to be 15 kilogram-meters. With the tripod and FGM-148 Javelin sight unit indirect fire configuration, British troops in Afghanistan used the L7A2 at ranges of and over. The average elevation of Afghanistan and accompanying low ISA air density significantly contribute to extending the useful maximum range of small-arms projectiles.
The L8A2 coaxial tank machine gun has a different gas valve switch when compared to the analogous Model 60-40, a different flash hider and a modified cocking handle. The weapon also has a trigger group that accepts electrical input and a lever in the feed tray that enables the belt to be removed without lifting the feed tray cover.
Another tank machine gun is the L37A2 designed to be mounted on tank turrets, in the commander's position, on wheeled armoured vehicles and on armored personnel carriers. It differs from the L8A2 primarily in its trigger, which was adapted from the L7A2 GPMG. The machine gun can be used in the ground role for self-defense, by dismounted vehicle crew members, the egress kit consists of an L7A2 barrel, bipod and buttstock.
The L20A1 aircraft machine gun was based on the L8A2, from which it differs by having an electrical trigger and a slotted flash suppressor. The L20A1 can be converted to right-hand feed by changing several components in the feed mechanism.
The L43A1, also developed from the L8A2, is a coaxially mounted tank machine gun used to sight-in the vehicle's main gun by firing ballistically matched tracer ammunition at the target to confirm the trajectory visually. The weapon's barrel, fitted with a flash hider, has a reinforced and heavier structure that increases the weapon's accuracy especially during sustained fire.'