The Minimi is a light machine gun firing from an open bolt. The weapon is primarily chambered for 5.56x45mm NATO, though a 7.62x51mm NATO variant exists. It is an air-cooled weapon, capable of fully automatic fire only. It can be belt fed or fired from a magazine.
The Minimi is configured in several variants, the Standard model as a platoon or squad support weapon, the Para version for paratroopers and the Vehicle model as secondary armament for fighting vehicles.
Design details
Operating mechanism
The Minimi uses a gas-actuated long-stroke piston system. The barrel is locked with a rotary bolt, equipped with two massive locking lugs, forced into battery by a helical camming guide in the bolt carrier. Upon firing, the piston is forced to the rear by expanding propellant gases bled through a port in the barrel near the muzzle end. The piston rod acts against the bolt carrier, which begins its rearward motion guided on two rails welded to the receiver walls, while the bolt itself remains locked. This sequence provides a slight delay that ensures chamber pressure has dropped to a safe level by the time a cam in the bolt carrier rotates and unlocks the bolt, increasing extraction reliability as the empty cartridge casing has had the time to cool down and contract, exerting less friction against the chamber walls.The Minimi fires from an open bolt, which reduces the danger of a round cooking off after extended periods of continuous fire, since a cartridge is only momentarily introduced into the chamber prior to ignition, and the movement of the bolt and bolt carrier forces air through the chamber and barrel after each shot, ventilating the barrel and removing heat. Gas escaping the gas cylinder is directed upward, avoiding kicking up dust and debris that would reveal the shooter's position.
Features
The Minimi has a manually adjustable gas valve with two positions, normal and adverse. The adverse setting increases the cyclic rate of fire from 700–850 rounds per minute to 950–1,150 rounds per minute and is used only in extreme environmental conditions or when heavy fouling is present in the weapon's gas tube. The spring extractor is located inside the bolt, while the tilting lever ejector is contained inside the receiver housing. Spent casings are removed through a port located at the bottom of the right side of the receiver, protected from debris with a spring-loaded dust cover. The Minimi is striker-fired and the bolt carrier functions as the striker mechanism.The Minimi has a push-button type manual safety installed in the trigger housing, above the pistol grip. In the "weapon safe" position, it disables the sear mechanism; pushing the button to the right side exposes a red-colored rim on the left side of the firearm and indicates the weapon is ready to fire. The black polymer pistol grip from the FAL and FNC rifles was initially used, but the Minimi is currently fitted with a modified grip with lateral grooves, installed at a smaller angle to the receiver.
The Minimi Para with a telescopic sight, spare barrel and ammunition pouches.
The standard light machine gun version has a 465 mm (18.3 in) barrel and a skeletonized aluminum stock with a folding wire shoulder strap. The shortened Para model has a 349 mm (13.7 in) barrel and a collapsible metal stock, while the vehicle-mounted model has a 465 mm (18.3 in) barrel but does not have a stock or iron sights. All models can alternatively be fitted with a fixed synthetic stock, the same used on the M249, which contains a hydraulic buffer that contributes to stabilizing the rate of fire and reducing recoil forces.
Feeding
The weapon is fed from the left-hand side by disintegrating-link M27 ammunition belts (a miniaturized version of the 7.62mm M13 belt), from either an unsupported loose belt, enclosed in a polymer ammunition box with a 200-round capacity attached to the base of the receiver, or from detachable STANAG magazines, used in other NATO 5.56mm assault rifles such as the M16 and FNC. Magazine feeding is used only as an auxiliary measure, when belted ammunition has been exhausted. The ammunition belt is introduced into the feed tray, magazines are seated inside the magazine port at a 45° angle, located beneath the feed tray port. When a belt is placed in the feed tray it covers the magazine port. Likewise, a magazine inserted into the magazine well will prevent the simultaneous insertion of a belt. The magazine port, when not in use, is closed with an L-shaped hinged flap equipped with a tooth, which engages a corresponding opening in the magazine and serves as a magazine release. This feature was developed by FN's Maurice V. Bourlet and allows the Minimi to be instantly changed from belt feed to magazine feed without any modification.
The pawl-type feeding mechanism is modeled on the system used in the MAG general purpose machine gun, which borrows from the World War II-era MG 42. The belt is moved in two stages during both the forward and rearward movement of the reciprocating bolt carrier, which provides for a smooth and continuous feeding cycle. The feeding mechanism top cover features a device that indicates the presence of a cartridge in the feed path.
Barrel
The barrels used in the Minimi have an increased heat capacity for sustained fire, feature a chrome-lined rifled bore (six right-hand grooves) and are manufactured in two versions: with a 178 mm (1:7 in) twist rate used to stabilize the heavier Belgian 5.56×45mm SS109 projectile, or a 305 mm (1:12 in) twist for use with American M193 ammunition. The barrels have a quick-change capability; a lever is provided on the left side of the weapon that releases the barrel from its trunnion. A carrying handle is also fixed to the barrel and assists in the barrel change process. A trained soldier can perform a barrel change and ready the weapon for aimed fire in 6–7 seconds. Early versions of the Minimi had a flash suppressor with side ports as seen on the FNC, CALcone-shaped slotted flash suppressor.Sights
Both the standard and Para models come with a rear sight, adjustable for windage and elevation, that provides a peep aperture for ranges from 300 to 1000 m in 100 m increments. The hooded front sight is installed in a post on the gas block and is also adjustable for elevation and windage. Early models of the Minimi had the rear sight mounted forward of the feed cover and the front post secured to the barrel, closer to the muzzle end. An adapter can also be used that allows the use of standard NATO night and day sights.Accessories
Standard equipment supplied with the Minimi consists of three ammunition boxes, a cleaning kit stored inside the forearm, lubricant bottle, sling and blank-firing adaptor.Variants
A U.S. Marine fires the PIP-upgraded M249 SAW.
As part of the US military's M249 Product Improvement Program (PIP), the M249 was updated with: a new synthetic stock and modified buffer assembly, a single-position gas regulator, a “birdcage” type flash hider/compensator from the M16A2, a polymer barrel heat guard, and a folding carry handle. As a result, the weapon’s weight increased to 7.47 kg (16.5 lb). Many of the PIP upgrades were later incorporated by FN for the Minimi.
A lightweight variant of the Para with a Picatinny top cover rail adapter is known as the Minimi Special Purpose Weapon (SPW). It had the magazine feed port removed to further reduce weight, and a railed MIL-STD-1913 handguard was used that enables the use of standard tactical accessories.
Another variant of the SPW requested by the US Special Operations Forces is the Mk 46 Mod 0 that incorporates a lightweight fluted barrel but lacks the magazine feed system, vehicle mounting lugs and carry handle. A railed forearm ensures modularity and mission-adaptability permitting the use of flashlights, vertical grips, and infrared laser designators. An improved variant known as the Mk 46 Mod 1 with an improved forward rail and lightweight titanium bipod has been adopted by the United States Navy.
The Minimi prototype was originally designed in 7.62x51mm NATO, and later redesigned around the 5.56mm cartridge. When the USSOCOM issued the requirements for the Mk 48 Mod 0, the original plans for the Minimi were retrieved and used to develop this new model. As a result of favorable reviews of the Mk 48 Mod 0 and increasing demand for a more powerful variant of the Minimi, FN Herstal introduced the Minimi 7.62, available in several different configurations. Apart from the different caliber, the Minimi 7.62 incorporates a non-adjustable, self-regulating gas system and a hydraulic recoil buffer in the buttstock assembly. The Minimi 7.62 also has a different sight setup calibrated for the larger cartridge. The rear sight is adjustable from 100 to 1,000 m by 100 m increments. The sight can also be corrected for windage. A variant of the Minimi 7.62 equipped with a railed Picatinny handguard is the Minimi 7.62 TR.
Copies of the Minimi have been produced in China, called the XY 5.56 x 45.
| Minimi | |
|---|---|
 An early M249 version of the Minimi. | |
| Type | Light machine gun |
| Place of origin |  Belgium |
| Service history | |
| Used by | See Users |
| Production history | |
| Designer | Ernest Vervier |
| Designed | 1974 |
| Manufacturer | FN Herstal |
| Produced | 1982–present |
| Variants | See Variants |
| Specifications | |
| Weight | Standard model: 6.85 kg (15.1 lb) Minimi Para: 6.56 kg (14.5 lb) Vehicle model: 5.32 kg (11.7 lb) Minimi 7.62: 8.17 kg (18.0 lb) fixed stock Minimi 7.62: 8.4 kg (19 lb) telescopic metal stock |
| Length | Standard model: 1,040 mm (40.9 in) Minimi Para: 914 mm (36.0 in) stock extended / 766 mm (30.2 in) stock collapsed Vehicle model: 793 mm (31.2 in) no buttstock Minimi 7.62: 1,015 mm (40.0 in) fixed stock Minimi 7.62: 1,000 mm (39.4 in) stock extended / 865 mm (34.1 in) stock collapsed[1] |
| Barrel length | Standard model: 465 mm (18.3 in) Minimi Para: 349 mm (13.7 in) Minimi 7.62: 502 mm (19.8 in) |
| Width | 110 mm (4.3 in) Minimi 7.62: 128 mm (5.0 in) |
| | |
| Cartridge | 5.56x45mm NATO Minimi 7.62: 7.62x51mm NATO |
| Action | Gas-operated, rotating bolt |
| Rate of fire | 700–1,150 rounds/min Minimi 7.62: 680-800 rounds/min |
| Muzzle velocity | Standard model: 925 m/s (3,035 ft/s) Minimi Para: 866 m/s (2,841.2 ft/s) |
| Effective range | 300–1,000 m sight adjustments |
| Feed system | 100-round M27 disintegrating-link belt, 30-round STANAG magazine |
| Sights | Rear aperture, front post. |
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