Gatling gun

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Image:Gatling gun 1865.jpg The Gatling gun was the first highly successful rapid-repeating firearm. It was the first firearm to combine reliability, high firing rate and ease of loading into a single device. It was designed by the American inventor Richard J. Gatling, in 1861 and patented on May 9, 1862. In modern usage it typically refers to guns with a similar rotating barrel design.

Depending on how one defines the term, the Gatling gun is not the first "machine gun", despite frequent references to it as such; machine guns operate entirely on the power of the fired cartridge ("internal power"), while the Gatling relies on a hand crank ("external power").

1 History of the gun
2 Basic design
3 Combat use
4 Modern Gatling guns
5 See also
6 External links

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History of the gun

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The Gatling gun was designed in 1861 during the U.S. Civil War. However, in 1862, the U.S. government did not purchase any, for the Gatling guns lacked triggers and were far too heavy to be set up quickly in combat. Even when Dr. Gatling improved the design, it still lacked the desired trigger and weighed an unwieldy 90 lb (41 kg). However, Union General Benjamin Butler bought twelve and used them successfully on the Petersburg front. During its debut in combat both Union and Confederate soldiers were awestruck by its power and effect. They were only put into limited service late in the war by the Northern army.

The Gatling gun was hand-crank operated with six barrels revolving around a central shaft, based on the Puckle Gun. Early models had a fibrous matting stuffed in among the barrels which could be soaked with water to cool the barrels down; this was eliminated in later models as being counterproductive. The ammunition, initially a steel cylinder charged with black powder and primed with a percussion cap (as self-contained brass cartridges had not yet been invented), was gravity-fed into the breech through a hopper or stick magazine on top of the gun. Each barrel had its own firing mechanism. After 1861, new brass cartridges similar to modern cartridges replaced the paper cartridge, but Gatling did not switch to them immediately.

The model of 1881 was designed to use the Bruce feed system (U.S. Patents 247,158 and 343,532) that would accept 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 1876 the Gatling gun could fire 1,200 rounds per minute, although 400 was more reasonable.

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Basic design

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The Gatling gun is a rotary device, originally powered using a crank. A cylinder of ten barrels, spaced equally around the side of the cylinder, rotates around a central axis. Each barrel fires once per revolution at about the same position.

Originally, the Gatling gun was produced in calibres ranging from one inch (25.4 mm) down to 0.45 inch (11.43 mm).

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. The carrier was grooved and the lock cylinder was drilled with holes corresponding to the barrels. 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. The casing was partitioned, and through this opening the barrel shaft was journaled. In front of the casing was a cam 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.

Turning the crank rotated the shaft. 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 cartridge which was then dropped to the ground.

The grouped barrel concept was not new; it had been tried 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 nipple 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 and breech.

The smallest calibre gun also had a Broadwell drum feed in place of the curved magazine of the other guns. The drum, named after L. W. Broadwell, an agent for Gatling's company, comprised twenty stick magazines 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 significant invention does not appear to have been patented separately, and may have been included in the April 9, 1872 patent, U.S. 125,563; a post and base, apparently for mounting a Broadwell drum, is visible in Figure 13 of U.S. 125,563. As each magazine emptied, the drum was manually rotated to bring a new magazine into use until all 400 rounds had been fired.

The Gatling gun was largely replaced after the development of the gas or recoil blowback concept, which is the basis of most modern machine guns. Such guns could be made smaller and lighter, and were less expensive to produce.

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Combat use

The Royal Navy used fixed Gatling guns on board warships, intended to repel boarders. By the mid-nineteenth century though, boarding ships was no longer practicable, and so the Gatlings mounted on board ships never saw close-range action.
The Naval Brigades serving during the Anglo-Zulu Wars used them alongside their artillery. At the Battle of Ulundi in 1879, Gatling guns were used to slaughter thousands of Zulu warriors who were forced to charge directly into their field of fire.
Gatling guns saw action during the British bombardment of Alexandria in 1882.
During the Franco-Prussian War of 1870-1871, several Gatling guns were purchased by Léon Gambetta on behalf of the Government of National Defense, and were used by the French armies fighting in the provinces, to replace the defective mitrailleuse
Gatling guns were used by the US side during the Spanish-American War, most notably during the battle of San Juan Hill. Some 31 gatling guns in all were purchased by the US Army before the war ended. [1]
Gatling guns were used throughout the Indian Wars against several Native American nations as the Western Expansion continued. The Battle of the Little Big Horn, in which George Armstrong Custer and his men were routed by combined Lakota and Cheyenne forces, could have had a very different outcome had Custer brought the Gatling guns that had originally been in his detail.

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Modern Gatling guns

Although the principle was unused for many years, Gatling-style guns with rotating barrels returned with the requirement for very high rate-of-fire weapons in military aircraft and ship-based anti-missile defence systems, with electric motors replacing mechanical cranks for rotation. One example is the M61 Vulcan 20 mm cannon, the most commonly used member of a family of weapons designed by General Electric and currently manufactured by General Dynamics. The Vulcan is a six-barrelled electric Gatling capable of firing more than 6,000 rounds per minute, a rate unachievable with a conventional machine gun. A variety of similar weapons are available in calibers ranging from 5.56 mm to 30 mm (There was even a 37mm Gatling that was mounted on the prototype T249 'Vigilante' anti-air platform), the rate of fire being somewhat inversely proportional to the size and mass of the ammunition (which also determines the size and mass of the barrels). During the Vietnam War, the 7.62 mm calibre M134 Minigun was created for helicopters as an offensive and defensive weapon. Able to fire 4,000 rounds a minute, the Minigun proved to be one of the deadliest weapons ever built and is used in helicopters today.

Versions of modern Gatling guns are also used with lethal effectiveness on USAF AC-130 and AC-119 Gunships. The airframes, originally designed as cargo planes, have an enormous capacity for lift and rounds of ammunition. With the sophisticated navigation and target indentification tools available to their crews, they pose a serious threat to any enemy. The crew's ability to concentrate the Gatling's fire very tightly produces the appearance of the 'Red Tornado' [[2]], from the tracers in the firing mix, as the gun platform circles and fires on a target at night.

In addition to their incredibly high rate of fire, many modern gatling guns have the advantage of being operated by external power sources (as opposed to being powered by the energy of the fired cartridge). This increases their reliability as a cartridge's failure to fire does not cause the weapon's operations cycle to be interrupted. In addition certain other classes of stoppage, such as faulty extraction and many of those associated with feeding, are eliminated or reduced considerably due to the external power source. It should however be noted that although uncommon and mechanically-complex, modern Gatling systems that derive operating power from the ammunition (like a normal firearm) do exist. In fact, the world's fastest-firing Gatling is one, being the aircraft-mounted 10'000RPM gas-operated Gryazev-Shipunov GSh-6-23.

The Gatling gun cameoed in the Arnold Schwarzenegger movie Predator where the character played by Jesse Ventura was armed with a M134 Minigun, although it would be impossible for a single person to actually carry and fire the Minigun because of the recoil. Indeed, the recoil in the movie's minigun was so great even though it was only firing blank ammunition that the actor had to be propped up in scenes where he fired the Minigun. Furthermore, it takes the equivalent of 6 car batteries to provide the current needed for the weapon's electric motor (a 28V DC/115V AC motor drawing 130A constantly, assuming that the minigun was firing at its maximum rate); the same gun would later be used in the film Terminator 2: Judgment Day. A similarly improbable use of a gatling gun appeared in the video game Metal Gear Solid, in which Vulcan Raven wielded a man-portable M61 Vulcan. A gatling gun also appeared in the movie The Last Samurai at the final battle between the Samurai and the Empire of Japan.