Assault rifle

An assault rifle is a selective fire rifle or carbine firing ammunition with muzzle energies intermediate between those typical of pistol and battle rifle ammunition. Assault rifles are categorized between light machine guns, intended more for sustained automatic fire in a support role, and submachine guns, which fire a handgun cartridge rather than a rifle cartridge. Assault rifles are the standard small arms in most modern armies, having largely replaced or supplemented larger, more powerful battle rifles, such as the World War II-era M1 Garand and Tokarev SVT. Examples of assault rifles include the AK-47 and the M16 rifle. Semi-automatic rifles, including commercial versions of the AR-15, and "automatic" rifles limited to firing single shots are not assault rifles as they are not selective fire. Belt-fed weapons or rifles with very limited capacity fixed magazines are also generally not considered assault rifles.

The term assault rifle is a translation of the German word Sturmgewehr (literally meaning "storm rifle"), "storm" used as a verb being synonymous with assault, as in "to storm the compound". Sturmgewehr was coined by Adolf Hitler to describe the Maschinenpistole 44, subsequently re-baptized Sturmgewehr 44, the firearm generally considered the first widely-used assault rifle and served to popularize the concept. The translation “assault rifle” gradually became the common term for similar firearms sharing the same technical definition as the name giver StG 44. In a strict definition, a firearm must have all of the following five characteristics to qualify as an assault rifle:[1][2][3]
Is a carbine sized individual weapon with provision to be fired from a shouldered position.
Barrel length is usually 400 mm to 500 mm (16” to 20”)
Is capable of selective fire.
Fires from a locked breech.
Utilizes an intermediate powered-cartridge.
Ammunition is supplied from a large capacity detachable box magazine.
Most common is a capacity of 30 rounds, sometimes 20 rounds.
The following features are commonly found on assault rifles, but those are not exclusive to assault rifles, as those features are shared with many submachine guns, battle rifles, automatic rifles and machine guns:
Protruding pistol grip.
Folding, retractable or otherwise collapsible shoulder stock.
Bipod
Muzzle device like a muzzle brake or a flash suppressor.
There are commentators who use the expression “assault rifle” more loosely to include other types of arms, particularly arms that fall under a strict definition of the battle rifle, or civilian semi-automatic off-shoots of military rifles for commercial or political reasons. Some militaries of nations outside of the English-speaking world also have a different definition of assault rifle. For instance, the analogous term in the Swedish Armed Forces is automatkarbin (literally "automatic carbine") which includes both assault rifles and battle rifles.

http://en.wikipedia.org/wiki/Assault_rifle