The Gatling gun was designed by the American inventor Dr. Richard J. Gatling in 1861 and patented on November 4, 1862. Gatling wrote that he created it to reduce the size of armies and so reduce the number of deaths by combat and disease, and to show how futile war is.
Although the first Gatling gun was capable of firing continuously, it required a person to crank it; therefore it was not a true automatic weapon. The Maxim gun, invented and patented in 1883, was the first true fully automatic weapon, making use of the fired projectile's recoil force to reload the weapon. Nonetheless, the Gatling gun represented a huge leap in firearm technology.
Prior to the Gatling gun, the only weapons available to militaries, capable of firing many projectiles in a short space of time, were mass-firing volley weapons like the French Reffye mitrailleuse in 1870–1871, and field cannons firing canister shot, much like a very large shotgun. The latter were widely used during and after the Napoleonic Wars. Although the maximum rate of fire was increased by firing multiple projectiles simultaneously, these weapons still needed to be reloaded after each discharge, which for multi-barrel systems like the mitrailleuse was cumbersome and time-consuming. This negated much of the advantage of their high rate of fire per discharge, making them much less powerful on the battlefield. In comparison, the Gatling gun offered a rapid and continuous rate of fire without having to be manually reloaded by opening the breech.
The original Gatling gun was a field weapon which used multiple rotating barrels turned by a hand crank, and firing loose (no links or belt) metal cartridge ammunition using a gravity feed system from a hopper. The Gatling gun's innovation lay in the use of multiple barrels to limit overheating, a rotating mechanism, and a gravity-feed reloading system, which allowed unskilled operators to achieve a relatively high rate of fire of 200 rounds per minute.