Semi-automatic firearm

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A semi-automatic firearm is a gun that requires only a trigger pull for each round that is fired, unlike a single-action revolver, a pump-action firearm, a bolt-action firearm, or a lever-action firearm, which require the shooter to manually chamber each successive round. For instance, if someone were to shoot ten rounds in a semi-automatic firearm, the trigger would need to be pulled ten times (once for each round fired), as opposed to a fully automatic firearm, which will continue to fire as long as the trigger is held or until it runs out of ammunition.

Firearms firing bursts of more than one round (usually three) per pull of the trigger, such as the M16A2 rifle, are generally considered fully automatic. Pistols, rifles, and shotguns can all be semi-automatic. A semi-automatic mode is a common choice on selective fire firearms.

Semi-automatic weapons are sometimes categorized as firing from an open bolt and firing from a closed bolt. When the trigger is pulled, the open bolt flies forward, picking up a cartridge from the magazine and pushing it into the chamber, firing the gun. The closed bolt system moves the bolt forward and picks up the cartridge as the last phases of the previous cycle, and when the trigger is pulled again only the firing pin moves. The closed bolt system is generally more accurate, since the center of gravity changes relatively little. The open bolt system is often used in submachine guns and support weapons, and rarely in firearms that can fire in semi-automatic mode only.

There is some dispute over the correct use of the words automatic and semi-automatic. Gun specialists sometimes argue that the word automatic is incorrectly taken to mean fully automatic fire and that an automatic weapon is simply any weapon that chambers a new round during the extraction of the previous cartridge's casing. The term is often used to mean a self-loading semi-automatic firearm rather than a fully automatic one. In practice, an automatic pistol usually means a self-loading semi-automatic pistol, but an automatic rifle usually means one capable of fully automatic fire. Both uses can be found, and the exact meaning must be determined from context.

The term "auto-loader" is commonly used to distinguish semi-automatic pistols from double-action revolvers.

[edit] Early history (1885–1945)

The first successful design for a semi-automatic rifle is attributed to German-born gunsmith Ferdinand Ritter von Mannlicher, who unveiled the design in 1885. Although Mannlicher earned his reputation with his bolt action rifle designs, he also produced a few semi-automatic pistols, including the Steyr Mannlicher M1894, which employed an unusual blow-forward action and held five rounds of 6.5mm ammunition that were fed into the M1894 by a stripper clip.

A few years later, American gunsmith John Moses Browning developed the first successful semi-automatic shotgun, the Browning Auto-5, which was first manufactured in 1902 by Fabrique Nationale de Herstal and sold in America under the Browning name. The Auto-5 relied on long recoil operation; this design remained the dominant form in semi-automatic shotguns for approximately 50 years. Production of the Auto-5 was finally ceased in 1999.

In 1906, Remington Arms introduced the "Remington Autoloading Repeating Rifle," also designed by Browning. This rifle, renamed the "Model 8" in 1911, was the first semi-automatic rifle designed especially for the civilian market, and was advertised as a sporting rifle by Remington. The rifle was offered in .25, .30, .32, and .35 caliber models, and gained popularity among civilians as well as some law enforcement officials who appreciated the combination of semi-automatic action and relatively powerful rifle cartridges. The Model 8 was superseded in 1936 by the Model 81.

The first semi-automatic rifle adopted and used by a major military Power (France) was Fusil Automatique Modele 1917. It was the first general issue self loading rifle and contained features that were seminal in its field. Features first found on the M1917 would later find their way into many later, more widely known, more widely produced designs. Like a venerable patriarch, the M1917 deserves recognition and respect as one of the most important and influential military longarms ever devised. Though the Garand is usually considered by some to be the first issued as a standard infantry weapon, the M1917 predates it and was used in the latter stages of WW1 and the Moroccan Rif war 1921-1926. The Garand was the gas-operated M1 Garand, developed by Canadian-born John Garand for Springfield Armory, which was owned by the US government. After years of research and testing, the first production model of the M1 Garand was unveiled in 1937. During World War II, the M1 Garand gave American infantrymen an overall advantage over their German opponents, many of whom still used bolt action rifles produced by Mauser.

[edit] Recent American legal debates (1988–Present)

As early as September 1988, Josh Sugarmann, gun-control activist and executive director of the Violence Policy Center, coined the term assault weapon to denote various semi-automatic firearms with features commonly associated with firearms used by military and/or law enforcement personnel. Sugarmann adopted the "assault weapon" label from the Sturmgewehr 44, a German military rifle used during World War II; Sturmgewehr translates into English as either "Storm Rifle" or "Assault Rifle." Note that this term is not synonymous with assault rifle, which has an established technical definition and refers only to military rifles with full-automatic capability. Sugarmann pushed for new legislation to restrict or outlaw civilian ownership of such firearms, stating that "The weapons' menacing looks, coupled with the public's confusion over fully automatic machine guns versus semi-automatic assault weapons -- anything that looks like a machine gun is assumed to be a machine gun -- can only increase the chance of public support for restrictions on these weapons."

Today, there is still no exact or universal definition for the term "assault weapon," although the term has gained significant popularity among gun-control advocates. However, a semi-automatic rifle, shotgun, or pistol is often legally defined an assault weapon if it features any number of the following characteristics...

A detachable magazine often called a "high-capacity" magazine
A folding or telescoping stock
A grenade launcher either built into the weapon or supplemental
A protruding pistol grip beneath the action of the firearm
A bayonet mount
A threaded barrel capable of accepting a flash suppressor or sound suppressor
A barrel shroud or other covering over a pistol barrel that permits the shooter to hold the firearm with the non-trigger hand without being burned
A magazine that attaches outside of the pistol grip (on pistols)

It should be noted that, without the select-fire feature of a true assault rifle, military-style semiautomatics are functionally no different from autoloading sporting firearms. The above mentioned features are largely cosmetic.

Exactly which characteristics should be used is a matter of debate and varies between jurisdictions. In the United States, nearly a dozen States have their own differing laws regulating or banning semi-automatic firearms of this type. There was also a federal Assault Weapons Ban in the United States which expired in 2004.