Automatic small arms were developed almost exclusively by inventors of American birth. A forerunner of the modern machine gun was built by R. J. Gatling during the Civil War. Later types of machine guns, which fired rifle bullets with great rapidity and whose firing mechanism worked by either the power of the gun's recoil or the force of the expanding gases, were developed by Hiram Maxim, B. Hotchkiss, I. N. Lewis, and J. M. Browning. Machine guns were used with terrible effectiveness in many colonial wars, especially by the British, Germans, and Americans, yet their effect on massed infantry still came as a horrible surprise to Europeans in the first year of World War I.
In the years just before and after World War I a host of new automatic small arms were developed. The automatic pistol to some extent replaced the revolver as the standard military sidearm; the revolver, however, remained the weapon of most police forces in the United States even though it has less fire power and carries less ammunition than the automatic pistol—mainly because, unlike the automatic, it did not jam. The submachine gun, a light, portable automatic weapon fired either from the hip or the shoulder, was sometimes employed by the Germans and Italians during World War I. In the United States, J. T. Thompson, in cooperation with J. N. Blish, perfected (1920) one of the first notable submachine guns. The Thompson submachine gun (nicknamed "tommygun" after its inventor) fires .45-caliber cartridges at a rate of 450 to 600 rounds per minute. It was used extensively in World War II as were more recently developed submachine guns such as the British Sten gun and the American weapon known as the M-3 or "grease gun" (because of its resemblance to the air-pressure devices used in automobile lubrication).
Just before World War I the automatic rifle, sometimes known as the light machine gun or machine rifle, was developed; part rifle, part machine gun, it is mounted on a bipod, has a shoulder stock, and is magazine-fed. Outstanding types of this weapon are the British Bren gun and the American Browning Automatic Rifle (BAR). During World War II the bolt-action rifle was supplanted by the semiautomatic Garand rifle—a clip-fed, gas-operated shoulder weapon weighing just over 9 lb (4.1 kg) and firing .30-caliber ammunition. It was the standard service rifle of the U.S. Army and Marine Corps during World War II and the Korean conflict.
After World War II, the United States and the Soviet Union adapted automatic rifles to the use of reduced-power bullets. The American M-16 rifle, which is widely used, can be fired accurately up to 500 yd (457 m) when hand-held and up to 800 yd (732 m) when mounted. The Soviet AK-47 Kalashnikov automatic rifle and the Israeli Uzi submachine gun are particularly effective and famous weapons.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.