An assault rifle is a rifle designed for combat, with selective fire (capable of shooting in both fully automatic and semi automatic modes). Assault rifles are the standard infantry weapons in most modern armies, having largely superseded or supplemented larger and more powerful battle rifles such as the M14, FN FAL and the Heckler & Koch G3. Examples of assault rifles include the M16 rifle, AK-47, G36, M4 carbine, and the Steyr AUG.
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." The name was coined by Adolf Hitler[1] to describe the Maschinenpistole 44, subsequently re-christened Sturmgewehr 44, the firearm generally considered the first true assault rifle that served to popularize the concept.
The translation assault rifle gradually became the common term for similar firearms sharing the same technical definition as the StG 44. In a strict definition, a firearm must have at least the following characteristics to be considered an assault rifle
It must be an individual weapon with provision to fire from the shoulder (i.e. a buttstock);
It must be capable of selective fire;
It must have an intermediate-power cartridge: more power than a pistol but less than a standard rifle or battle rifle;
Its ammunition must be supplied from a detachable box magazine.
Rifles that meet most of these criteria, but not all, are technically not assault rifles despite frequently being considered as such. For example, semi-automatic-only rifles that share designs with assault rifles such as the AR-15 (which the M-16 rifle is based on) are not assault rifles, as they are not capable of switching to automatic fire and thus not selective fire. Belt-fed weapons (such as the M249 SAW) or rifles with fixed magazines are likewise not assault rifles because they do not have detachable box magazines.
The term "assault rifle" is often more loosely used for commercial or political reasons to include other types of arms, particularly arms that fall under a strict definition of the battle rifle, or semi-automatic variant of military rifles such as AR-15s
The US Army defines assault rifles as "short, compact, selective-fire weapons that fire a cartridge intermediate in power between submachinegun and rifle cartridges.
Primarily limited to the United States, the term assault weapon is a term used to describe a variety of semi-automatic firearms that have certain features generally associated with military assault rifles. The 1994 Federal Assault Weapons Ban, which expired on September 13, 2004, defined the rifle type of assault weapon as a semiautomatic firearm with the ability to accept a detachable magazine, and two or more of the following featurers:
Folding or telescoping stock
Conspicuous pistol grip
Bayonet mount
Flash suppressor, or threaded barrel designed to accommodate one
Grenade launcher
Barrel shroud