The Gatling gun's operation centered on a cyclic multi-barrel design which facilitated cooling and synchronized the firing-reloading sequence. As the handwheel is cranked, the barrels rotate, and each barrel sequentially loads a singlecartridge from a top-mountedmagazine, fires off the shot when it reaches a set position (usually at4 o'clock), then ejects the spent casing out of the left side at the bottom, after which the barrel is empty and allowed to cool until rotated back to the top position and gravity-fed another new round. This configuration eliminated the need for a singlereciprocatingbolt design and allowed higher rates of fire to be achieved without the barrels overheating quickly.
The Gatling gun is operated by a hand-crank mechanism, with six barrels revolving around a central shaft (although some models had as many as ten). Each barrel fires once per revolution at about the same position. The barrels, a carrier, and a lock cylinder were separate and all mounted on a solid plate revolving around a central shaft, mounted on an oblong fixed frame. Turning the crank rotated the shaft. The carrier was grooved and the lock cylinder was drilled with holes corresponding to the barrels.
The casing was partitioned, and through this opening, the barrel shaft wasjournaled. In front of the casing was acam with spiral surfaces. The cam imparted a reciprocating motion to the locks when the gun rotated. Also in the casing was a cocking ring with projections to cock and fire the gun. Each barrel had a single lock, working in the lock cylinder on a line with the barrel. The lock cylinder was encased and joined to the frame. Early models had a fibrous matting stuffed in among the barrels, which could be soaked with water to cool the barrels down. Later models eliminated the matting jacketing as being unnecessary.
Cartridges, held in a hopper, dropped individually into the grooves of the carrier. The lock was simultaneously forced by the cam to move forward and load the cartridge, and when the cam was at its highest point, the cocking ring freed the lock and fired the cartridge. 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 aunitary 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 apercussion cap on one end. As the barrels rotated, these steel cylinders dropped into place, were fired, and were then ejected from the gun. The innovative features of the Gatling gun were its independent firing mechanism for each barrel and the simultaneous action of the locks, barrels, carrier, andbreech.
The ammunition that Gatling eventually implemented was apaper cartridge charged with black powder and primed with a percussion cap because self-contained brass cartridges were not yet fully developed and available. 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. Each barrel had its own firing mechanism.
Despite self-contained brass cartridges replacing the paper cartridge in the 1860s, it was only in the Model 1881 that Gatling switched to the 'Bruce'-style feed system (U.S. Patents 247,158 and 343,532) which accepted two rows of.45-70 cartridges. While one row was being fed into the gun, the other could be reloaded, thus allowing sustained fire. The final gun required four operators. By 1886, the gun was capable of firing more than 400 rounds per minute.
The smallest-caliber gun also had a Broadwell drum feed in place of the curved box of the other guns. The drum, named afterL. W. Broadwell, an agent for Gatling's company, comprised twenty stacks of rounds arranged around a central axis, like the spokes of a wheel, each holding twenty cartridges with the bullet noses oriented toward the central axis. This invention was patented in U. S. 110,338. As each stack emptied, the drum was manually rotated to bring a new stack into use until all 400 rounds had been fired. A more common variant had 240 rounds in twenty stands of fifteen.
By 1893, the Gatling was adapted to take the new.30 Army smokeless cartridge. The new M1893 guns featured six barrels, later increased to ten barrels, and were capable of a maximum (initial) rate of fire of 800–900 rounds per minute, though 600 rpm was recommended for continuous fire.[15][18] Dr. Gatling later used examples of the M1893 powered by electric motor and belt to drive the crank.[19] Tests demonstrated the electric Gatling could fire bursts of up to 1,500 rpm.
The M1893, with minor revisions, became the M1895, and 94 guns were produced for the U.S. Army by Colt. Four M1895 Gatlings under LieutenantJohn H. Parker saw considerable combat during the Santiago campaign in Cuba in 1898. The M1895 was designed to accept only the Bruce feeder. All previous models were unpainted, but the M1895 was painted olive drab green, with some parts leftblued.
Model 1900 was very similar to Model 1895 but with only a few components finished in O.D. green. The U.S. Army purchased several M1900s. All Gatling Models 1895-1903 could be mounted on an armored field carriage. In 1903, the Army converted its M1900 guns into .30 Army to fit the new.30-03 cartridge (standardized for the M1903 Springfield rifle) as the M1903. The later M1903-'06 was an M1903 converted to.30-06. This conversion was principally carried out at the Army's Springfield Armory arsenal repair shops. All models of Gatling guns were declared obsolete by the U.S. military in 1911, after 45 years of service.[20]
The original Gatling gun was a field weapon that used multiple rotating barrels turned by a handcrank, and firing loose (no links or belt) metal cartridge ammunition using agravity 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.[21]
Although the first Gatling gun was capable of firing continuously, it required a person to crank it and so it was not a trueautomatic weapon. TheMaxim 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 infirearm technology.
Before the Gatling gun, the only weapons available to military forces that could fire many projectiles in a short period of time were mass-firingvolley weapons, like the Belgian and Frenchmitrailleuse of the 1860s and 1870s, and fieldcannons firingcanister shot, much like an upsizedshotgun. The latter was widely used during and after theNapoleonic Wars. Although the maximumrate of fire was increased by firing multiple projectiles simultaneously, those weapons still needed to be reloaded after each discharge, which for multi-barrel systems like themitrailleuse was cumbersome and time-consuming. That negated much of the advantage of their high rate of fire per discharge by 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.
Early multi-barrel guns were approximately the size and weight ofartillery pieces and were often perceived as a replacement for cannons firinggrapeshot or canister shot.[22] Compared with earlier weapons such as themitrailleuse, which required manual reloading, the Gatling gun was more reliable and easier to operate and had a lower, but continuous rate of fire. The large wheels required to move these guns around required a high firing position, which increased the vulnerability of their crews.[22]
Sustained firing ofblack powder cartridges generated a cloud of smoke, making concealment impossible untilsmokeless powder became available in the late 19th century.[23] When operators were firing Gatling guns against troops of industrialized nations, they were at risk, being vulnerable to artillery they could not reach andsnipers they could not see.[22]
Patent drawing for R. J. Gatling's "battery gun", 9 May 1865
The Gatling gun was designed by the American inventorRichard J. Gatling in 1861 and patented on November 4, 1862.[24][21] Gatling wrote that he created it to reduce the size of armies and so reduce the number of deaths by combat and disease.[25]
The US Army adopted Gatling guns in several calibers, including .42 caliber,.45-70, .50 caliber, 1 inch, and (M1893 and later).30 Army, with conversions of M1900 weapons to.30-03 and.30-06.[26][27] The .45-70 weapon was also mounted on someUS Navy ships of the 1880s and 1890s.[28]
The British manufacturer James George Accles, previously employed by Colt 1867–1886, developed a modified Gatling gun circa 1888 known as the Accles Machine Gun.[29] Circa 1895, theAmerican Ordnance Company acquired the rights to manufacture and distribute this weapon in the Americas. It was trialed by the US Navy in December 1895, and was said to be the only weapon to complete the trial out of five competing weapons, but was apparently not adopted by US forces.[30]
The Gatling gun was first used in warfare during theAmerican Civil War. Twelve of the guns were purchased personally by Union commanders and used in the trenches during theSiege of Petersburg, Virginia (June 1864—April 1865).[31] Eight other Gatling guns were fitted on gunboats.[32] The gun was not accepted by the American Army until 1866 when a sales representative of the manufacturing company demonstrated it in combat.[22]
CaptainLuis Germán Astete of thePeruvian Navy took with him dozens of Gatling guns from the United States to Peru in December 1879 during the Peru-ChileWar of the Pacific. Gatling guns were used by the Peruvian Navy and Army, especially in theBattle of Tacna (May 1880) and theBattle of San Juan (January 1881) against the invading Chilean Army.
In 1888, theSS Ozama smuggled a number of Gatling guns into Haiti[35]
In 1907, Gatling guns were used by Nicaragua in the battle of Namasique, largely manned by American mercenaries[36]
Gatling guns were kept in store by coal companies and used during theBattle of Blair Mountain;[37] On September 1, a group of miners looted one of these guns and assaulted a spot called Craddock Fork. Opposing forces fought back with a machine gun, but after three hours of heavy fire, their weapon jammed. The miners surged forward and briefly broke the defensive line, but were repulsed by another machine gun nest located further up the ridge.[38]
According to Ellis, the Russians were amongst the first to realize the potential of machine guns, testing two Gatlings in 1865 and promptly ordering twenty for theImperial Russian Army, eventually obtaining a license to build them locally. By 1876, the Russians had 400 Gatlings organized in eight batteries; While McNab stated that the Russians were introduced to the Gatling in 1871, when Colonel Aleksandr Pavlovich Gorloff was given a demonstration, and impressed by what he saw, ordered 400 Gatlings for the Imperial Army. Both accounts agree that these guns, known in Russia as theGorloffs first saw action during theRusso-Turkish War (1877–1878),[39][40] where they were effectively used at theBattle of Nikopol and theSiege of Plevna. TheGorloff gun was also used during theRussian conquest of Central Asia to repelTurkmen cavalry charges.[39]
The Gatling gun was used most successfully to expand European colonial empires by defeating indigenous warriors mounting massed attacks, including theZulu, theBedouin, and theMahdists.[22] TheBritish Army first deployed the Gatling gun in 1873-74 during theAnglo-Ashanti wars, and extensively during the last actions of the 1879Anglo-Zulu war.[41] TheRoyal Navy used Gatling guns during the 1882Anglo-Egyptian War.[23]
Gatling guns were used byEgyptian forces both on sea and land and saw combat in Sudan and Abyssinia.Isma'il Pasha ordered 120 Colt 1865 six-barrel Gatling guns; after being convinced by Shahine Pasha who witnessed Gatling gun trials at Shoeburyness in 1866. In 1872 a few ''camel'' guns were purchased, these were smaller and used a tripod instead of the carriage. During theSiege of Khartoum an Egyptian Gatling gun aided by a telescope was able to target Sudanese artillery crews from a distance of 2,000 yards.[42]
Gatling guns were imported by some states in Nigeria. They were used during the Kalabari Civil war of 1879–83,[43] the Abbi House bought one from King Jaja of Opobo and it may have been used in canoe warfare.[44] The Ijesha used a Gatling gun against the Ibadan during the early 1880s.[43] In 1882 the Bonny used a Gatling gun during an attack on New Calabar.[45]
By 1880,Siam had imported an unknown number of Gatlings. By 1885 the kingdom had a Gatling Gun regiment of 600 men; those weapons were possibly used in theHaw Wars. They were also seen among Prince Bigit's escort in 1886.[46]
TheKorean Empire possessed a number of Gatlings. 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 pleasedEmperor Gojong). Some of them were deployed to defend the approaches of the capital during theDonghak Rebellion, but there is no evidence they saw combat.[47]
Because of infighting within army ordnance, Gatling guns were used by the U.S. Army during theSpanish–American War.[48] A four-gun battery of Model 1895 ten-barrel Gatling guns in.30 Army, made byColt's Arms Company, was formed into a separate detachment led byLt. John "Gatling Gun" Parker.[49] The detachment proved very effective, supporting the advance of American forces at theBattle of San Juan Hill. Three of the Gatlings with swivel mountings were used with great success against the Spanish defenders.[15] During the American charge up San Juan and Kettle hills, the three guns fired a total of 18,000 .30 Army rounds in8+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][50]
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, theU.S. Marines had been issued the modern tripod-mountedM1895 Colt–Browning machine gun using the6mm Lee Navy round, which they employed to defeat the Spanish infantry at the battle ofCuzco Wells.
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. However, some examples were developed during the interwar years, but only existed as prototypes or were rarely used. The concept resurfaced after World War II with the development of theMinigun and theM61 Vulcan in particular for use in aircraft over reciprocating bolt autocannons which are more prone to jamming inhigh g environments. Other versions of the Gatling gun were built from the late 20th century to the present, the largest of them being the 30mmGAU-8 Avenger autocannon as used on theFairchild Republic A-10 Thunderbolt II.[citation needed]
^abcdParker, John H. (Lt.),The Gatlings At Santiago, Middlesex, UK: Echo Library (reprinted 2006)
^Chambers, John W. (II) (2000)."San Juan Hill, Battle of".The Oxford Companion to American Military History.Archived from the original on November 26, 2009. RetrievedNovember 24, 2009.
^U.S. Ordnance Dept.,Handbook of the Gatling Gun, Caliber .30 Models of 1895, 1900, and 1903, Washington, D.C.: Government Printing Office, (1905) p. 21
^Heath, Ian (2003) [1998].Armies of the Nineteenth Century: Burma and Indo-China. Foundry Books. p. 155.ISBN978-1-90154-306-3.
^Heath, Ian (1998).Armies of the nineteenth century. Asia : organisation, warfare, dress, and weapons. St. Peter Port, Guernsey: Foundry Books.ISBN1-901543-01-3.OCLC50089869.
^Patrick McSherry."Gatling". spanamwar.com. Archived fromthe original on May 9, 2018. RetrievedNovember 3, 2015.
^Parker, John H. (Lt.),History of the Gatling Gun Detachment, Kansas City, MO: Hudson-Kimberly Publishing Co. (1898), pp. 20, 23–32
^Parker, John H.: Cranked by hand at its highest speed until the first magazine of ammunition had been emptied, the M1895 .30 Gatling Gun had an initial rate of fire of 800–900 rounds per minute.
^Linn, B. M., 2000, The Philippine War, 1899–1902, Lawrence: University Press of Kansas,ISBN0700612254
^Chinn, George Morgan, "The Machine Gun: History, Evolution and Development of Manual, Automatic and Airborne Repeating Weapons, Volume 1" U.S. Government Printing Office, (1951)
^Drury, Ian, "The Russo-Turkish War 1877": Osprey Publishing (1994)