The Gatling gun's operation centered on a cyclic multi-barrel design which facilitated cooling and synchronized the firing-reloading sequence.

This configuration eliminated the need for a single reciprocating bolt design and allowed higher rates of fire to be achieved without the barrels overheating quickly.

One of the best-known early rapid-fire firearms, the Gatling gun saw occasional use by the U.S. forces during the American Civil War, which was the first time it was employed in combat.

After the cartridge was fired the continuing action of the cam drew back the lock bringing with it the spent casing which then dropped to the ground.

The grouped barrel concept had been explored by inventors since the 18th century, but poor engineering and the lack of a unitary cartridge made previous designs unsuccessful.

The initial Gatling gun design used self-contained, reloadable steel cylinders with a chamber holding a ball and black-powder charge, and a percussion cap on one end.

The shells were gravity-fed into the breech through a hopper or simple box "magazine" with an unsprung gravity follower on top of the gun.

[20] The original Gatling gun was a field weapon that 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.

In comparison, the Gatling gun offered a rapid and continuous rate of fire without having to be manually reloaded by opening the breech.

Early multi-barrel guns were approximately the size and weight of artillery pieces and were often perceived as a replacement for cannons firing grapeshot or canister shot.

[22] Compared with earlier weapons such as the mitrailleuse, which required manual reloading, the Gatling gun was more reliable and easier to operate and had a lower, but continuous rate of fire.

[23] When operators were firing Gatling guns against troops of industrialized nations, they were at risk, being vulnerable to artillery they could not reach and snipers they could not see.

In April 1867, a Gatling gun was purchased for the Argentine Army by minister Domingo F. Sarmiento under instructions from president Bartolomé Mitre.

[34] Captain Luis Germán Astete of the Peruvian Navy took with him dozens of Gatling guns from the United States to Peru in December 1879 during the Peru-Chile War of the Pacific.

The miners surged forward and briefly broke the defensive line, but were repulsed by another machine gun nest located further up the ridge.

[38] The Gatling gun was used most successfully to expand European colonial empires by defeating indigenous warriors mounting massed attacks, including the Zulu, the Bedouin, and the Mahdists.

During the Siege of Khartoum an Egyptian Gatling gun aided by a telescope was able to target Sudanese artillery crews from a distance of 2,000 yards.

Six had been imported in 1884, by 1891 it had a battery of fourteen guns and in 1894 the army's two American drilled regiments had as many as 40 Gatlings and practiced regularly (Supposedly because the noise pleased Emperor Gojong).

[15] During the American charge up San Juan and Kettle hills, the three guns fired a total of 18,000 .30 Army rounds in 8+1⁄2 minutes (an average of over 700 rounds per minute per gun of continuous fire) against Spanish troop positions along the crest of both hills, causing significant casualties.

[15][49] Despite this successful deployment, the Gatling's weight and cumbersome artillery carriage hindered its ability to keep up with infantry forces over difficult ground, particularly in Cuba, where roads were often little more than jungle footpaths.

By this time, the U.S. Marines had been issued the modern tripod-mounted M1895 Colt–Browning machine gun using the 6mm Lee Navy round, which they employed to defeat the Spanish infantry at the battle of Cuzco Wells.

[50] The Gatling's weight and artillery carriage hindered its ability to keep up with American troops over uneven terrain, particularly in the Philippines, where outside the cities there were heavily foliaged forests and steep mountain paths.

After the Gatling gun was replaced in service by newer recoil or gas-operated weapons, the approach of using multiple externally powered rotating barrels fell into disuse for many decades.

Other versions of the Gatling gun were built from the late 20th century to the present, the largest of these being the 30mm GAU-8 Avenger autocannon as used on the Fairchild Republic A-10 Thunderbolt II.