Richard Gatling patented his ferocious weapon in the early 1860s and the type was subsequently used in the American Civil War to deadly effect. The basic principle revolved around a steady feed of ammunition supplied to ten rotating barrels to help prevent the barrels from overheating. Rotation of the barrels were hand-cranked by the operator/aimer. A second soldier would insert a fresh forty-round magazine into the top of the weapon as needed. Magazines were fed from a large vertical "hopper".
Gatling guns came in a variety of calibers following the Civil War and these included the .45, .50 and even a 1-inch caliber. Despite its impressive 350-to-400 rounds per minute rate-of-fire, such an instrument was none-the-less prone to jamming.
Transportation was provided for by two large, multi-spoked wheels to either side of the weapon. The wheels were attached to an axle which also served as the base mounting for the gun itself. A tow system at the rear of the gun allowed connection to another two-wheeled axle system carrying ammunition supply boxes. The entire unit could then be carted by horse or pack mules as needed.
Despite its potential, the Gatling Gun saw little action along the Western Frontier in post-war America. Teddy Roosevelt's Rough Riders made use of no fewer than four Gatling Guns in their battle up San Juan Hill in Puerto Rico, resulting in an American/Cuban victory over the Kingdom of Spain. Gatling Guns also defended Fort Davis in Texas for a time, these being Model 1865 versions firing new rimfire copper-based cartridges.