The GAU-13 was developed in the late 1970s for use in gun pod applications for fighter aircraft and attack aircraft use, primarily for air-to-ground and anti-tank attacks.
The GAU-13/A is a four-barreled rotary cannon based on the mechanism of the larger GAU-8, sharing the same massive 30 mm ammunition. Like the Avenger, it has a double-ended feed system with reverse clearing to remove unfired rounds. Unlike the GAU-8, however, it is pneumatically driven, giving it a rate of fire of 2,400 rounds per minute. Minimum time between stoppages is estimated at 32,000 rounds, making it a very reliable weapon.
The GAU-13/A uses the same range of PGU-13 High Explosive Incendiary (HEI) and PGU-14 Armor-Piercing Incendiary (API) rounds (which contain a depleted uranium penetrator) as the Avenger. Despite its somewhat lower rate of fire compared to the seven-barreled Avenger, it is an immensely powerful weapon.
The principal application for the GAU-13/A was the GPU-5/A gun pod (originally marketed as the GEPOD 30). The pod is 4.3 m (14 ft 2 in) long and can be mounted on any standard NATO 762 mm (30 in) suspension lugs. It holds 353 rounds of ammunition, enough for approximately nine seconds of continuous fire. The GPU-5/A weight is 600 kg (1,325 lb) empty and 841 kg (1,854 lb) fully loaded. The pod is completely self-contained.
