Lance Cpl. Joseph E. Miller, Marine Light Attack Helicopter Squadron 269 UH-1Y Huey crew chief, mans the GAU-17 minigun, Nov. 28. The minigun is a six-barrel electrically-operated machine gun that has a firing rate of 2,000-4,000 rounds per minute and is mounted on vehicles, helicopters and boats. - Lance Cpl. Joseph E. Miller, Marine Light Attack Helicopter Squadron 269 UH-1Y Huey crew chief, mans the GAU-17 minigun, Nov. 28. The minigun is a six-barrel electrically-operated machine gun that has a firing rate of 2,000-4,000 rounds per minute and is mounted on vehicles, helicopters and boats.