The GAU-19 is a minigun of US origin. It was developed by General Electric in the early 1980's to complement the smaller caliber M134 and was called the GECAL 50 at first. The GAU-19 is used as armament on helicopters, vehicles and ships. Compared to other weapons in this caliber the GAU-19 has a much higher rate of fire at increased costs and enormous weapon, mount and ammunition weight.

The GAU-19 functions in a similar way as the earlier M134. Many components differ in size to accomodate the larger caliber. The GAU-19 is based on the Gatling principle with multiple rotating barrels and is externally powered by batteries. Early models had six barrels but three barrel models are most common. A feed chute feeds from left to right using standard 12.7mm rounds and belts. The weapon swivels vertically in a single arm which also allows the weapon to traverse. The operator uses a joystick-like spade grip and aims by means of mechanical or optical sights on top of the weapon.

The GAU-19 fires standard 12.7x99mm ammunition using normal M9 link belts. The cyclic rate of fire is a selectable 1.000 or 2.000 rpm. When used in the HMMWV mount there only is a single rate of fire of 1.300 rpm. New types of rounds such as SLAP can be fired, while ammunition produced before 1983 may result in problems. The effective range is quoted as 1.800 meters, with the slant range being 6 km. The barrels need to be changed every 50.000 rounds.

The GAU-19 is used by the USA and has been exported to several nations. The GAU-19 is not as widely used as the smaller M134. This is probably since it is more expensive and much heavier, especially regarding the ammunition.