Shotgun
A shotgun is a long-barreled firearm designed to shoot a straight-walled cartridge known as a shotshell, which discharges numerous small spherical projectiles called shot, or a single solid projectile called a slug. Shotguns are most commonly used as smoothbore firearms, meaning that their gun barrels have no rifling on the inner wall, but rifled barrels for shooting sabot slugs are also available.
Shotguns come in a wide variety of calibers and gauges ranging from 5.5 mm to up to, though the 12-gauge and 20-gauge bores are by far the most common. Almost all are breechloading, and can be single barreled, double barreled, or in the form of a combination gun. Like rifles, shotguns also come in a range of different action types, both single-shot and repeating. For non-repeating designs, over-and-under and side-by-side break action shotguns are by far the most common variants. Although revolving shotguns do exist, most modern repeating shotguns are either pump action or semi-automatic, and also fully automatic, lever-action, or bolt-action to a lesser extent.
Preceding smoothbore firearms were widely used by European militaries from the 17th until the mid-19th century. The muzzleloading blunderbuss, the direct ancestor of the shotgun, was also used in similar roles from self-defense to riot control. Shotguns were often favored by cavalry troops in the early to mid-19th century because of its ease of use and generally good effectiveness on the move, as well as by coachmen for its substantial power. However, by the late 19th century, these weapons became largely replaced on the battlefield by breechloading rifled firearms shooting spin-stabilized cylindro-conoidal bullets, which were far more accurate with longer effective ranges. The military value of shotguns was rediscovered in the First World War, when American forces used the pump-action Winchester Model 1897 shotgun in trench fighting to great effect. Since then, shotguns have been used in a variety of close-quarters combat roles in civilian, law enforcement, and military applications.
The smoothbore shotgun barrel generates less resistance and thus allows greater propellant loads for heavier projectiles without as much risk of overpressure or a squib load, and are also easier to clean. The shot pellets from a shotshell are propelled indirectly through a wadding inside the shell and scatter upon leaving the barrel, which is usually choked at the muzzle end to control the projectile scatter. This means each shotgun discharge will produce a cluster of impact points instead of a single point of impact like other firearms. Having multiple projectiles also means the muzzle energy is divided among the pellets, leaving each individual projectile with less penetrative kinetic energy. The lack of spin stabilization and the generally suboptimal aerodynamic shape of the shot pellets also make them less accurate and decelerate quite quickly in flight due to drag, giving shotguns short effective ranges. In a hunting context, this makes shotguns useful primarily for hunting fast-flying birds and other agile small/medium-sized game without risking overpenetration and stray shots to distant bystanders and objects. However, in a military or law enforcement context, the high short-range blunt knockback force and large number of projectiles makes the shotgun useful as a door breaching tool, a crowd control or close-quarters defensive weapon. Militants or insurgents may use shotguns in asymmetric engagements, as shotguns are commonly owned civilian weapons in many countries. Shotguns are also used for target-shooting sports such as skeet, trap, and sporting clays, which involve flying clay disks, known as "clay pigeons", thrown in various ways by a dedicated launching device called a "trap".
History
Most early firearms, such as the blunderbuss, arquebus, and musket had large diameter, smoothbore barrels, and could fire shot as well as solid balls. A firearm intended for use in wing shooting of birds was known as a fowling piece. The 1728 Cyclopaedia defines a fowling piece as:For example, the Brown Bess musket, in service with the British army from 1722 to 1838, had a 19 mm smoothbore barrel, roughly the same as a 10-gauge shotgun, and was long, just short of the above recommended 168 cm. On the other hand, records from the Plymouth Colony show a maximum length of 137 cm for fowling pieces, shorter than the typical musket.
Shot was also used in warfare; the buck and ball loading, combining a musket ball with three or six buckshot, was used throughout the history of the smoothbore musket. The first recorded use of the term shotgun was in 1776 in Kentucky. It was noted as part of the "frontier language of the West" by James Fenimore Cooper.
With the adoption of smaller bores and rifled barrels, the shotgun began to emerge as a separate entity. Shotguns have long been the preferred method for sport hunting of birds, and the largest shotguns, the punt guns, were used for commercial hunting. The double-barreled shotgun has changed little since the development of the boxlock action in 1875. Modern innovations such as interchangeable chokes and subgauge inserts make the double-barreled shotgun the shotgun of choice in skeet, trap shooting, and sporting clays, as well as with many hunters.
As wing shooting has been a prestige sport, specialty gunsmiths such as Krieghoff or Perazzi have produced fancy double-barrel guns for wealthy European and American hunters. These weapons can cost US$5,000 or more; some elaborately decorated presentation guns have sold for up to US$100,000.
During its long history, the shotgun has been favored by bird hunters, guards, and law enforcement officials. The shotgun has fallen in and out of favor with military forces several times in its long history. Shotguns and similar weapons are simpler than long-range rifles, and were developed earlier. The development of more accurate and deadlier long-range rifles minimized the usefulness of the shotgun on the open battlefields of European wars. But armies have "rediscovered" the shotgun for specialty uses many times.
19th century
During the 19th century, shotguns were mainly employed by cavalry units. Both sides of the American Civil War employed shotguns. U.S. cavalry used the shotgun extensively during the Indian Wars in the latter half of the 19th century. Mounted units favored the shotgun for its moving target effectiveness, and devastating close-range firepower. The shotgun was also favored by citizen militias and similar groups.With the exception of cavalry units, the shotgun saw less and less use throughout the 19th century on the battlefield. As a defense weapon, it remained popular with guards and lawmen, however, and the shotgun became one of many symbols of the American Old West. Lawman Cody Lyons killed two men with a shotgun; his friend Doc Holliday's only confirmed kill was with a shotgun. The weapon both these men used was the short-barreled version favored by private strongbox guards on stages and trains. These guards, called express messengers, became known as shotgun messengers, since they rode with the weapon for defense against bandits. Passenger carriages carrying a strongbox usually had at least one private guard armed with a shotgun riding in front of the coach, next to the driver. This practice has survived in American slang; the term "riding shotgun" is used for the passenger who sits in the front passenger seat. The shotgun was a popular weapon for personal protection in the American Old West, requiring less skill on the part of the user than a revolver.
Hammerless shotguns
The origins of the hammerless shotgun are European but otherwise obscure. The earliest breechloading shotguns originated in France and Belgium in the early 19th century and a number of them such as those by Robert and Chateauvillard from the 1830s and 1840s did not use hammers. In fact during these decades a wide variety of ingenious weapons, including rifles, adopted what is now often known as a "needle-fire" method of igniting the charge, where a firing pin or a longer sharper needle provided the necessary impact. The most widely used British hammerless needle-fire shotgun was the unusual hinged-chamber fixed-barrel breech-loader by Joseph Needham, produced from the 1850s. By the 1860s, hammerless guns were increasingly used in Europe both in war and sport, although hammer guns were still very much in the majority. The first significant encroachment on hammer guns was a hammerless patent which could be used with a conventional side-lock. This was British gunmaker T. Murcott's 1871 action nicknamed the "mousetrap" on account of its loud snap action. However, the most successful hammerless innovation of the 1870s was Anson and Deeley's boxlock patent of 1875. This simple but ingenious design only used four moving parts allowing the production of cheaper and reliable shotguns.Daniel Myron LeFever is credited with the invention of the American hammerless shotgun. Working for Barber & LeFever in Syracuse, New York, he introduced his first hammerless shotgun in 1878. This gun was cocked with external cocking levers on the side of the breech. He went on to patent the first truly automatic hammerless shotgun in 1883. This gun automatically cocked itself when the breech was closed. He later developed the mechanism to automatically eject the shells when the breech was opened.
John Moses Browning
One of the men most responsible for the modern development of the shotgun was prolific gun designer John Browning. While working for Winchester Firearms, Browning revolutionized shotgun design. In 1887, Browning introduced the Model 1887 Lever Action Repeating Shotgun, which loaded a fresh cartridge from its internal magazine by the operation of the action lever. Before this time, most shotguns were the break-open type.This development was greatly overshadowed by two further innovations he introduced at the end of the 19th century. In 1893, Browning produced the Model 1893 Pump Action Shotgun, introducing the now familiar pump action to the market. And in 1900, he patented the Browning Auto-5, America's first semi-automatic shotgun. The first semi-automatic shotgun in the world was patented in 1891–1893 by the Clair brothers of France. The Browning Auto-5 remained in production until 1998.