The Gatling gun is a machine gun that has many barrels that fire bullets by turning the barrels around in a circle. It was the first machine gun ever made. It was first used during the Union Army during the American Civil War. Although it was very powerful, its use was limited because it was expensive and heavy. However, it was used more often in many other wars during the later half of the 20th century and the very beginning of the 21st century, including the Anglo-Zulu War, the Boshin War, and the Spanish-American War. The Gatling gun was the gun that the Minigun is based on. Interestingly, the Gatling gun is a machine gun, but it is not called an automatic weapon because you cannot shoot by holding down the trigger, but you must keep moving your arms.