M134 Minigun

The M134 Minigun is a 7.62x51 mm NATO, six-barreled machine gun with a high rate of fire (2,000 to 6,000 rounds per minute). It features Gatling-style rotating barrels with an external power source, normally an electric motor. The "Mini" of the name is in comparison to designs that use a similar firing mechanism but larger shells, such as General Electric's earlier 20-millimeter M61 Vulcan, and "gun" for a caliber size smaller than that of a cannon, typically 20 mm and higher.

"Minigun" refers to a specific model of weapon that General Electric originally produced, but the term "minigun" has popularly come to refer to any externally powered Gatling gun of rifle caliber. The term is also used to refer to guns of similar rates of fire and configuration regardless of power source and caliber.

The basic minigun is a six-barrel, air-cooled, and electrically driven rotary machine gun. The electric drive rotates the weapon within its housing, with a rotating firing pin assembly and rotary chamber. The minigun's multi-barrel design helps prevent overheating, but also serves other functions. Multiple barrels allow for a greater capacity for a high firing rate, since the serial process of firing/extraction/loading is taking place in all barrels simultaneously. Thus, as one barrel fires, two others are in different stages of shell extraction and another three are being loaded. The minigun is composed of multiple closed-bolt rifle barrels arranged in a circular housing. The barrels are rotated by an external power source, usually electric, pneumatic, or hydraulic. Other rotating-barrel cannons are powered by the gas pressure or recoil energy of fired cartridges. A gas-operated variant, designated the XM133, was also developed. It is near identical but has barrels with ports that align with the piston drive in the center of the barrel cluster. It fired over 3000 rpm but was not put into production.

While the weapon can feed from linked ammunition, it requires a delinking feeder to strip the links as the rounds are introduced to the chambers. The original unit was designated MAU-56/A, but has since been replaced by an improved MAU-201/A unit.

Weight 85 pounds [47.8 lightweight mod.]
Length 801.6 mm
Barrel length 558.8 mm
Cartridge 7.62×51mm NATO
Caliber 7.62 mm (0.308 in)
Action Electrically driven rotary breech
Rate of fire Variable, 2,000–6,000 rpm
Muzzle velocity 2,800 ft/sec (853 m/s)
Maximum range 3,280 ft (1,000 m, 1,093 yd)
Feed system Disintegrating cartridge belt or linkless feed; dependent on installation [500-5,000 round belt]
Sights Dependent on installation; no fixed sights


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