The Gatling gun featured a circle of ten barrels attached to a rotating shaft turned by a hand‐operated crank, which drove the entire device. As the barrels revolved, they passed by a firing hammer that discharged the cartridge, which was automatically ejected and replaced by a new breech‐loaded cartridge from a gravity‐fed hopper. The gun could be fired continuously as long as the crank was turned; externally powered Gatling guns could fire up to 3,000 rounds a minute.
Despite their obvious potential against infantry attacks, Gatling guns were infrequently used during the Civil War. Gen. James W. Ripley, the Union army's chief of ordnance, opposed their development, due to suspicion of Gatling's Southern birth and concern about the weapon's reliability and the enormous supply of munitions such guns would require. The U.S. Army eventually adopted the Gatling gun, assigning the large wheeled, horse‐drawn weapons and their munitions limbers, to artillery units that used them in the Plains Indians Wars and in the Spanish‐American War. The U.S. Army replaced these with smaller, lighter, and recoil‐powered modern machine guns in the twentieth century.
Joseph Berk , The Gatling Gun: 19th Century Machine Gun to 21st Century Vulcan, 1991.
T. R. Brereton
Gat·ling gun / ˈgatling/ (also Gat·ling) • n. a rapid-fire, crank-driven gun with a cylindrical cluster of several barrels. The first practical machine gun, it was officially adopted by the U.S. Army in 1866.