Semi-automatic weapon: Wikis


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The M1 Garand was the first semi-automatic rifle to be generally issued to the infantry in any nation's army.

A semi-automatic firearm, or self-loading firearm is a gun that after being fired, ejects the empty round that has been fired, loads a new cartridge, and usually also cocks itself. This mechanism is different from a single-action revolver, a pump-action firearm, a bolt-action firearm, or a lever-action firearm; all of which require the shooter to cock the weapon manually before each shot and eject each empty round afterwards (these are called repeating fireams). For example, to fire ten rounds in a semi-automatic firearm, the trigger would need to be pulled ten times (once for each round fired) without cocking the weapon manually in between shots, in contrast to a fully automatic firearm, which can continue to fire as long as the trigger is held until it runs out of ammunition.

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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[1]. The Model 85 was followed by the equally innovative Mannlicher Models 91, 93 and 95 semi-automatic rifles.[2] 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 6.5 mm ammunition that were fed into the M1894 by a stripper clip.

Semi-automatic shotgun

Remington 1100 Tactical Shotgun in 12 gauge - an example of a semi-automatic shotgun

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.

Blowback semi-automatic

In 1903 and 1905, the Winchester Repeating Arms Company introduced the first semi-automatic rim-fire and center-fire rifles designed especially for the civilian market. The Winchester Model 1903 and Winchester Model 1905 operated on the principle of delayed blowback in order to function semi-automatically. Designed entirely by T.C. Johnson, the Winchester Model 1903 achieved commercial success and continued to be manufactured to 1932 when the Winchester Model 63 replaced it.

By the early 20th century, several manufacturers had introduced semi-automatic .22 sporting rifles, including Winchester, Remington, Fabrique Nationale and Savage Arms, all using the direct blow-back system of operation. Winchester introduced a medium caliber semi-automatic sporting rifle, the model 1907 as an upgrade to the Model 1905, utilizing a delayed blowback system of operation, in calibers such as .351 Winchester. Both the Models of 1905 and 1907 saw limited military and police use.

Recoil Operated Rifles

In 1906, Remington Arms introduced the "Remington Auto-loading Repeating Rifle," also designed by Browning. Remington advertised this rifle, renamed the "Model 8" in 1911, as a sporting rifle. This is a locked breech, recoil operated action. 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 81 superseded the Model 8 in 1936 and was offered in .300 Savage as well as the original Remington calibers.

The first semi-automatic rifle adopted and used by a major military power (France) was the Fusil Automatique Modele 1917. This too is a locked breech, recoil operated action.It was the first general issue self-loading rifle and contained features that were seminal in its field. A number of features first found on the M1917 would later find their way into many later, more widely known, more widely produced designs. The M1917 was used in the latter stages of WWI and the Moroccan Rif war 1921-1926. Following World War I, the French military converted many of the M1917 to manual operation. The Lebel bolt action rifle remained the standard French infantry rifle until replaced in 1936 by the MAS.

Other nations experimented with self-loading rifles between the two World Wars, including Britain, which had intended to replace the bolt-action Lee-Enfield with a self-loader, possibly chambered for sub-caliber ammunition, but discarded that plan as the imminence of the Second World War and the emphasis shifted from replacing every rifle with a new design to speeding-up re-armament with existing weapons. The Soviet Union and Germany would both issue successful self-loading and selective-fire rifles on a large scale during the course of the war, but not in sufficient numbers to replace their standard bolt-action rifles.

Gas Operated Rifles

There was much experimentation between the World Wars in gas operated semi-automatic rifles, largely for military application.

The U.S. M1 Garand is generally recognised as the first semi-automatic rifle to replace its nation's bolt action rifle as the standard issue infantry rifle. The gas-operated M1 Garand was 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, of whom most were still issued the Mauser 98 bolt-action rifle.

The Russian Tokarev (SVT 38 and SVT 40 with more than 1 Millions produced) and German G43 semi-automatic gas operated rifles were issued in World War II in relatively small numbers and did not replace the bolt action rifle as a standard infantry weapon.

The SKS is a semi-automatic Russian rifle

Another famous gas operated semi automatic rifle developed toward the end of WWII was the SKS. Designed by Sergei Gavrilovich Simonov in 1945, it came equipped with a bayonet and could hold ten rounds fed by a stripper clip. It didn't see very much combat, since it was quickly replaced by the AK-47. It was the first weapon chambered to use the cartridge 7.62x39mm, which had a medium amount of recoil.

Types of semi-automatic

There are semi-automatic pistols, rifles, and shotguns designed and made as semi-automatic only. Selective fire firearms are capable of both full automatic and semi-automatic modes.

Semi-automatic

Semi-automatic refers to a firearms which uses the force of recoil or gas to eject the empty cartridge casing and load a cartridge in the firing chamber for the next shot and which allows repeat shots solely through the action of pulling the trigger. A double-action revolver also requires only a trigger pull for each round that is fired but is not considered semi-automatic since the manual action of pulling the trigger is what advances the cylinder, not energy of the preceding shot.

Fully Automatic compared to Semi-automatic

The usage of the term automatic may vary according to context. Gun specialists point out that the word automatic is sometimes misunderstood to mean fully automatic fire when used to refer to a self-loading, semi-automatic firearm not capable of fully automatic fire. In this case, automatic refers to the loading mechanism, not the firing capability.

Walther P99, a semi-automatic pistol from the late 1990s

The term "automatic pistol" almost exclusively refers to a semi-automatic (i.e. not fully automatic) pistol. With handguns, the term "automatic" is commonly used to distinguish semi-automatic pistols from revolvers. The term "auto-loader" may also be used to describe a semi-automatic handgun. However, the term "automatic rifle" may mean a rifle capable of fully automatic fire. Both uses of the term "automatic" can be found, and the exact meaning must be determined from context.

Auto-loading

Semi-automatic

The mechanism of semi-automatic (or auto-loading) firearms is usually what is known as a closed bolt firing system. In a closed-bolt system, a round must first be chambered manually before the weapon can fire. When the trigger is pulled, only the hammer and firing pin move, striking and firing the cartridge. The bolt then recoils far enough rearward to extract and load a new cartridge from the magazine into the firearm's chamber, ready to fire again once the trigger is pulled.

An open bolt mechanism is a common characteristic of fully automatic firearms. With this system, pulling the trigger releases the bolt from a cocked, rearward position, pushing a cartridge from the magazine into the chamber, firing the gun. The bolt retracts to the rearward position, ready to strip the next cartridge from the magazine. The open-bolt system is often used in submachine guns and other weapons with a high rate of fire. It is rarely used in semi-automatic-only firearms, which can fire only one shot with each pull of the trigger. The closed-bolt system is generally more accurate; since the center of gravity changes relatively little at the moment the trigger is pulled.

With full automatic weapons, open bolt operation allows air to circulate cooling the barrel; with semi-automatic firearms, the closed bolt operation is preferred as over-heating is not as critical, and accuracy is preferred in semi-automatic operation. Some select fire military weapons use open bolt in full automatic mode and closed bolt when semi-automatic is selected.

Problems

Semi-automatic firearms, though effective in combat, are also prone to many problems. The most notable of these problems is the slamfire. This occurs when the bolt is released but the force of it closing is powerful enough to detonate the primer. This may happen multiple times with a single magazine.

Like all auto loading firearms, semi-automatics are also prone to jamming. This can happen during the feeding cycle when the cartridge gets stuck while entering the firing chamber, or during the ejection cycle when the fired casing may become stuck while exiting the chamber.

Also, due to the large variance in the loadings and power of shotshells, semi-automatic shotguns may not be able to fully cycle low power or specialty loads. When shooting these loads, the action may have to be manually cycled. While manually cycling the action may not be a big problem, some actions may or may not cycle loads from the same box. This can be troublesome to the operator, who may assume that the action did not fully cycle, but accidentally eject an unfired load when the action did cycle properly. The action may fail to eject the hull, eject the hull but not load another shell, or cycle properly.

See also

References

  1. ^ Ferdinand Ritter von Mannlicher
  2. ^ Walter H.B. Smith, Mannlicher Rifles and Pistols, Military Service Publishing Comapny, 1947.

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