firearms designed primarily to be carried and fired by one person and, generally, held in the hands, as distinguished from heavy arms, or artillery.
The first small arms came into general use at the end of the 14th cent. Initially they were nothing more than a small cannon held in the hands, fired by placing a lighted match at the touchhole; later a stock was added. The matchlock, the first real handgun, was fired by pulling a trigger that moved a lighted match to the touchhole; it was superseded by the wheel lock, which was fired by a spark-producing mechanism that ignited the gunpowder. By the end of the 16th cent. the wheel lock had been replaced by the flintlock, in which flint striking against steel produced a spark to fire the powder. Early matchlocks, wheel locks, and flintlocks bore many different names; common types included the musket, harquebus, and pistol. The musket was a heavy military firearm designed to be fired from the shoulder; the harquebus, an earlier and heavier weapon, was fired from a support. The pistol, in contrast, was designed to be held and fired with one hand.
The rifle, invented in the 15th cent., is a firearm with a grooved, or rifled, bore that imparts a spinning motion to the bullet, giving it greater accuracy. (The principle of rifling the inner surface of the barrel is applied also to artillery.) Rifles first came into widespread practical use in the E United States. Because of its slow rate of fire and its manufacturing cost, the rifle remained relatively unused as a military weapon in Europe. Until the middle of the 19th cent. the musket was the standard small arm.
In the early 19th cent. firearms were revolutionized by the invention of the percussion-cap method of igniting gunpowder. The percussion cap was a small metal capsule, filled with fulminate of mercury, that exploded when struck and fired the gun instantly; it soon replaced the flintlock. Another important advance was the development of gas-expanding bullets, such as the minié and Burton bullets, in the 1840s. In 1855 the United States adopted a new form of firearm called the rifled musket—a gun that looked like a musket, used the minié bullet, had a rifled barrel, was muzzle-loaded, and was fired by percussion caps. It was used by both sides in the U.S. Civil War. Thereafter all small arms became rifled with the exception of the shotgun, a smoothbore firearm designed for short-range firing of either a single slug or a number of small shot. Shotguns are either double-barreled or single-barreled and can be single-shot or repeaters; they are used mainly for hunting.
Although gunsmiths had experimented with breech-loading cannon and small arms almost since the invention of firearms, it was not until c.1870 that practical breech-loading firearms came into general use. By the 1880s magazine loading, smokeless powder, and the bolt action had also been developed in Europe and the United States and were in general use in military small arms.
Although the earliest examples of the revolver date from the second half of the 16th cent., and a usable multifiring weapon of the pistol type, called the “pepperbox,” appeared in the first quarter of the 19th cent., it was not until Samuel Colt patented his revolving pistol that the revolver won a place as one of the world's standard small arms. Colt's weapon was a pistol with a revolving cylinder, capable of firing several shots without reloading. The revolver and the magazine-loading rifle were the standard small arms throughout the world in the last part of the 19th cent. until the invention of automatic firearms shortly before 1900.
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.