The M134 Minigun is an American 7.62×51mm NATO six-barrel rotary machine gun with a high rate of fire (2,000 to 6,000 rounds per minute).

[6] None of these German guns went into production during the war, although a competing Siemens prototype (possibly using a different action), which was tried on the Western Front, scored a victory in aerial combat.

[7] In the 1960s, the United States Armed Forces began exploring modern variants of the electrically powered, rotating barrel Gatling-style weapons for use in the Vietnam War.

Although helicopters had mounted single-barrel machine guns, using them to repel attackers hidden in the dense jungle foliage often led to overheated barrels or cartridge jams.

[8] To develop a more reliable weapon with a higher rate of fire, General Electric designers scaled down the rotary-barrel 20 mm M61 Vulcan cannon for 7.62×51mm NATO ammunition.

Word of Dillon's efforts to improve the Minigun reached the 160th SOAR, and the company was invited to Fort Campbell, Kentucky, to demonstrate its products.

A delinker, used to separate cartridges from ammunition belts and feed them into the gun housing, and other parts were tested on Campbell's ranges.

The gun then went through the Army's formal procurement system approval process, and in 2003 the Dillon Aero minigun was certified and designated M134D.

[12] Garwood Industries made several other modifications to the 1960s Minigun design in order to meet modern-day military and ISO standards.

Garwood submitted false paperwork to the ATF claiming that some M134G rotor housings had been destroyed when they were actually sold to the gun-running ring.

[21][22] A separate variant, designated XM196, with an added ejection sprocket was developed specifically for the XM53 Armament Subsystem on the Lockheed AH-56 Cheyenne helicopter.

The primary end users of the GAU-17/A have been the USN and the United States Marine Corps (USMC), which mount the gun as defensive armament on a number of helicopters and surface ships.

GAU-17/As from helicopters were rushed into service for ships on pintle mountings taken from Mk16 20 mm guns for anti-swarm protection in the Gulf ahead of the 2003 Iraq War - 59 systems were installed in 30 days.

These gun pods were used by a wide variety of fixed- and rotary-wing aircraft mainly during the Vietnam War, remaining in inventory for a period afterward.

The standard pod, designated SUU-11/A by the Air Force and M18 by the U.S. Army, was a relatively simple unit, completely self-contained, with a 1,500-round magazine directly feeding delinked ammunition into the weapon.

Initially on fixed-wing gunships such as the Douglas AC-47 Spooky and Fairchild AC-119, the side-firing armament was fitted by combining SUU-11/A aircraft pods, often with their aerodynamic front fairings removed, with a locally fabricated mount.

[30] By the end of the year, the difficulties had been worked out and the units were again being fitted to AC-47s, AC-119s, and AC-130s, with a specific ammunition load that replaced every fifth 'ball' round with a tracer round to enable better accuracy by the gunners, and also earning these airborne gunships the nickname 'Puff the Magic Dragon' by the Viet Cong due to their apparent ability of spitting fire and making everything they hit disappear or die.

[citation needed] The improved MXU-470/As were even being proposed for lighter aircraft such as the Cessna O-2 Skymaster[31] used by Forward Air Controllers but proved too heavy and cumbersome.

A fit of two MXU-470/As was also tested on the Fairchild AU-23A Peacemaker, though the Royal Thai Air Force later elected to use another configuration with the M197 20 mm cannon.

The system is entirely self-contained, so it can be mounted on any aircraft that can handle the weight, rotational torque, and recoil force (190 lbf (850 N)) of the gun.

The first systems utilized the weapon in a forward firing role for a variety of helicopters, some of the most prominent examples being the M21 armament subsystem for the UH-1 and the M27 for the OH-6.

The weapon was also used as a pintle-mounted door gun on a wide variety of transport helicopters, a role it continues to fulfill today.