The M134 Minigun, also known as the M134 GAU-17 “Vulcan” cannon, has a variable rate of fire that can range from 2,000 to 6,000 rounds per minute (rpm). In most applications, the rate of fire is set between 3,000 and 4,000 rpm. The Minigun is a six-barreled, air-cooled, medium machine gun that uses an electronic rotary drive to achieve its high rate of fire. The gun's barrels rotate rapidly, similar to the principle invented by Richard J. Gatling in the 1860s. The Minigun is primarily used as a fire suppression weapon in aircraft by the U.S. military.