A machine gun is a fully automatic mounted or portable firearm, usually designed to fire rounds in quick succession from an ammunition belt or large-capacity magazine, typically at a rate of several hundred rounds per minute.
Machine Gun MG3 (MG1A3): The MG3 (MG1A3) is an open, fully automatic weapon for sustained firing and firing in bursts. It is a “recoil-operated weapon” in which the recoil forces are used to feed and load the cartridges and to extract and eject the spent cartridge cases. A blain firing attachment which is screwed onto the muzzle instead of the recoil booster permits the use of blank cartridges for training and exercise purpose.
FN MAG: 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. 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 four 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).
FN Minimi: 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.
LSAT Light Machine Gun: The LMG design is a traditionally (non-bullpup) laid-out machine-gun. It has many of the capabilities of other light machine guns, such as a quick-change barrel, a vented fore-grip, belt-fed ammunition, an ammunition pouch, and a roughly 600 rpm rate of fire. New features include the unique weight, a rounds counter, and a highly stiff and heat resistant barrel achieved with fluting and special materials.
M249 Light Machine Gun: The M249 is a belt-fed light machine gun. It fires the 5.56×45 mm NATO cartridge; usually a combination of one M856 tracer and four M855 ball cartridges fed from M27 linked belts. Belts are typically held in a hard plastic or soft canvas box attached to the underside of the weapon. It fires from an open bolt and is gas operated. A cartridge is stripped from the belt, chambered, and discharged, sending a bullet down the bore. At 1,041 mm (41 in) long and 7.5 kg (17 lb) in weight (10 kg (22 lb) including a 200-round belt and plastic ammo box), the M249 is a cumbersome weapon. The barrel has a rifling twist rate of one turn in 180 mm (7 in). Because firing heats up the bore, the air-cooled barrel is equipped with a mechanism to remove and replace the barrel assembly with a spare. A folding bipod with adjustable legs is attached near the front of the weapon, though there are provisions for hard-mounting to a M192 Lightweight Ground Mount tripod or vehicle mount. The M249 provides accuracy approaching that of a rifle, combined with the sustained volume of fire of a machine gun.
FN BRG-15: The BRG-15 had almost been fully developed when the project was finally terminated. The weapon’s chambering was in a unique 15.5x106mm cartridge developed especially for the weapon, replacing 15.5x115mm cartridge originally planned, because of fast barrel wear. It also utilized an unusual dual feed device (A la Hafdasa C-4), with link ammunition belts feeding from both the right and left. Spent shell casings were ejected out of the bottom of the gun, as in FN’s later P90 personal defense weapon. The quick-change barrel assembly developed for the BRG-15 was redesigned for use in an updated version of the M2HB.
Kord Machine Gun: The Kord-12.7 mm heavy machine gun is a Russian design that entered service in 1998 replacing the older NSV machine gun. Externally the weapon resembles the NSV, however the internal mechanism has been extensively reworked, changing from a horizontally pivoting breech block to a rotating bolt design. Additionally the gas system has been changed and the muzzle baffle redesigned. These changes give the weapon reduced recoil compared with the NSV, allowing greater accuracy during sustained fire.
CIS 50MG: The one unique feature of the CIS 50MG is its dual belt-feed system, the system allows for fast and easy switching of ammunition from standard ball rounds to the Raufoss Mk 211 Armor-Piercing-Incendiary rounds or the Saboted light armor penetrator (SLAP), which are capable of penetrating a rolled homogeneous armor plate with a thickness of 25 mm (0.98 in) from a range of 1 km (0.62 mi). Such systems are more commonly used in modern automatic cannons such as the M242 Bushmaster 25mm cannon and the Mk44 Bushmaster II 30mm cannon, both of which are also in use by the Singapore Army’s Bionix AFVs.
Zastava M72: The Zastava M72 chambers and fires the 7.62x39mm M43 round. It is a gas-operated, air-cooled, drum-fed firearm with a fixed stock. This weapon is a near copy of the Soviet RPK light machine gun. There are a few differences on the M72/M72A. It does not have a scope side rail mount; the butt is also different, having the shape of a regular AK-47 rifle. It has a reinforced receiver, night sights and no carrying handle. The barrel also differs from other RPK rifles because of the cooling fins to help with heat dissipation from prolonged fire. The M72 only appears with a heavy profile barrel as opposed to Russian and Romanian RPK rifles that can come in both light and heavy barrel configurations.
Ultimax 100: The Ultimax 100, also known as the “Section Machine Gun” is a gas-operated automatic weapon (capable of fully automatic fire only) with a short-stroke gas piston operating system powered by ignited powder gases diverted from the barrel through a port in the gas block. The Ultimax 100 is a locked breech weapon with a rotating bolt that contains 7 locking lugs. It fires from an open bolt position. The bolt contains both a spring extractor and a casing ejector. The magazine catch consists of two tapered pins on a bar, controlled by the magazine release button. The machine gun feeds from a proprietary 100-round synthetic drum magazine (early models also used 60-round drum magazines), or from a modified 20 or 30-round STANAG 4179 magazine (from the M16 rifle).