Minigun - Wikipedia, the free encyclopedia
The
Minigun is a multibarreled
machine gun with a high rate of fire (several thousand
rounds per minute), employing
Gatling-style rotating barrels and an external power source. In popular culture the term has come to refer to any externally powered Gatling gun of rifle caliber, though the term is sometimes used to refer to guns of similar rates of fire and configuration regardless of power source and caliber. Specifically, the term Minigun refers to a single weapon, originally produced by General Electric. The "mini" of the name is in comparison to designs that use a similar firing mechanism but 20 mm or larger shells, such as General Electric's earlier
M61 Vulcan.
1890s: Electric motor-driven Gatling gun
The ancestor to the modern minigun was made in the 1860s. Richard J. Gatling replaced the hand cranked mechanism of a rifle-caliber
Gatling gun with an electric motor, a relatively new invention at the time. Even after Gatling slowed down the mechanism, the new electric-powered Gatling gun had a theoretical rate of fire of 3,000 rounds per minute, roughly three times the rate of a typical modern, single-barreled machine gun. Gatling's electric-powered design received US Patent #502,185 on
July 25,
1893. Despite Gatling's improvements, the Gatling gun fell into disuse after cheaper, lighter-weight, recoil and gas operated machine guns were invented.
1960s: Vietnam war
In the 1960s, the US military began exploring modern variants of the electric-powered, rotating barrel Gatling gun-style weapons for use in the
Vietnam War. The US forces in Vietnam, which used helicopters as one of the primary means of transporting soldiers and equipment through the dense jungle, found that the thin-skinned helicopters were very vulnerable to small arms fire and Rocket-Propelled Grenade attacks when they slowed down to land. Although helicopters had mounted single-barrel machine guns, using single-barrel machine guns to repel attackers hidden in the dense jungle foliage often led to barrels overheating or cartridge jams.
In order to develop a weapon with a more reliable, higher rate of fire,
General Electric designers scaled down the rotating-barrel 20 mm
M61 Vulcan cannon for
7.62 x 51 mm NATO ammunition. The resulting weapon, designated
XM134 and known popularly as the
Minigun, could fire up to 6,000 rounds per minute without overheating. The Minigun was mounted on
OH-6 Cayuse and
OH-58 Kiowa side pods, in the turret and wing pods on
AH-1 Cobra attack helicopters, on door, pylon and pod mounts on
UH-1 "Huey" Iroquois transport helicopters, and on many other helicopters and aircraft.
The minigun's multibarrel 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, but was not put into production.
Several larger aircraft were outfitted with miniguns, specifically for
close air support, including famous
gunship airplanes like the
Douglas AC-47 ("Spooky" a.k.a. "
Puff the Magic Dragon", converted
Douglas C-47s),
AC-119 Gunship ("Shadow" and "Stinger", converted
Fairchild "
Flying Boxcars"), and the original
AC-130 "Spectre" Gunship (converted
C-130 Hercules cargo planes), the H-53 (
MH-53 Pave Low), and the common H-60 family of helicopters (
UH-60 Black Hawk/
HH-60 Pave Hawk) transport helicopters - a replacement for the aforementioned
UH-1 Iroquois. More rarely, the minigun was mounted on Vietnam-era tanks.
Variants
US Army Designation US Air Force Designation US Navy Designation Description XM134/M134 GAU-2/A N/A 7.62x51 mm NATO GE “Minigun” 6-barreled machine gun N/A GAU-2A/A N/A GAU-2/A variant; unknown differences N/A GAU-2B/A Mk 25 Mod 0 GAU-2A/A variant; unknown differences N/A GAU-17/A N/A GAU-2B/A variant; optimized for flexible use, uses either a MAU-201/A or MAU-56/A delinking feeder. XM196 N/A N/A M134/GAU-2B/A variant; housing modified by addition of an ejection sprocket; for use in the
XM53 armament subsystem on the
AH-56 helicopter G.E.'s minigun is in use in all major branches of the US military, under a number of designations. The basic fixed armament version was given the designation
M134 by the U.S. Army, while the exact same weapon was designated
GAU-2B/A by the U.S. Air Force. A variant was further developed by the U.S. Air Force specifically for flexible installations, at the time primarily for the
UH-1N helicopter, as the GAU-17/A. The primary end users of the
GAU-17/A have been the U.S. Navy and the U.S. Marine Corps, who mount them on as defensive armament on a number of helicopters and surface ships.
Other manufacturers in the United States also produce Miniguns with various refinements of their own, including Dillon Aerospace (the "M134D"), and Garwood Industries (the "M134G").
The GE 7.62x51 mm Minigun has been used in
gun pod applications by the United States and with purpose-built mounting hardware used on the aforementioned fixed wing gunship aircraft. In fact, before the purpose-built mounts were created, those aircraft used mounts simply designed to hold the gun pods that had already been developed.
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