GAU-8 Avenger

An up-close look at the GAU-8 gatling gun on the A-10. — GAU-8 Avenger

Manufacturer: General Electric

Service: USAF Weight: 619.5 lb Total Length: 19 ft 10.5 in Barrel Length: 90.5 in Width: 17.2 in Caliber: 30 mm Barrels: 7 Max Rate of Fire: 4,200 rpm Muzzle Velocity: 3,500 ft/s Maximum Range: 3,660 m

The AN/GAU-8 Avenger 30mm gun system was specifically built to serve as a Close Air Support "Tank Buster" for the U.S. Air Force. Similar to the earlier M61 20mm Vulcan design, the Avenger uses seven barrels to achieve a rate of fire of 3,900 rounds per minute.

The Avenger fires a mix of 30mm electrically primed PGU-13/B High Explosive Incendiary (HEI) rounds and PGU-14/B Armor Piercing Incendiary (API) rounds. While the HEI rounds provide the Avenger the ability to destroy light skinned vehicles, the weapon's real punch is delivered by the API rounds, each of which incorporates over half a pound of super-dense Depleted Uranium. At 1,200 meters (4,000 feet) a 2-second burst from the AN/GAU-8 will deliver 100 rounds containing 65 pounds of DU and place 80 percent of these projectiles within 20 feet of the target.

The AN/GAU-8 is used exclusively by the United States Air Force A-10 Thunderbolt II, a dedicated Close Air Support aircraft which was essentially designed around the Avenger gun system.

On Nov. 16, 1970, the Air Force issued a request for proposal for a 30mm rapid fire cannon to use in the A-X Close Air Support aircraft. In June of 1971 General Electric and Philco Ford were selected to build the prototype gun, designated GAU-8. Besides development of the gun, the contract called for the development of four types of ammunition: Armor Piercing Incendiary, High Explosive Incendiary, Semi-Armor Piercing High Explosive and Target Practice.

The first in-flight testing of the GAU-8 was done on Feb. 26, 1974. The gun was fired for the first time in flight with combat ammunition on June 19, 1974. The Avenger fired more than 39,000 rounds of ammunition during approximately 60 test flights. The gun was tested in a wide variety of flight profiles: from as high as 25,000 feet to as low as 100 feet; at speeds ranging from 135 knots to 415 knots; in all attitudes (various roll, pitch and yaw) with up to five G's.

The test program went smoothly and the first test mission cancellation didn't occur until Nov. 12, 1975, when the gun jammed. The test program identified a few problems including gun residue buildup on the canopy and problems with gun gas ingestion into the engines. Both problems were solved and fixes were incorporated into production aircraft beginning with aircraft No. 16 (earlier aircraft were retrofitted with the fixes).