The versatile, Austrian-made (Steyr Mannlicher designed and produced) 5.56mm assault rifle was designed in the early 1970s. The Steyr AUG or Armee Universal Gewehr (Universal Army Rifle) was adopted by the Austrian Federal Army (Bundesheer) as the StG 77 in 1977, when it replaced the aging, 7.62mm, StG 58 automatic rifle.

In production since 1978, the AUG is the Bundesheer'sstandard small arm. This multi-faceted assault rifle has been adopted by the armed forces of several countries, to include Argentina, Australia, New Zealand, Bolivia, Ecuador, Ireland and Saudi Arabia. Closer to home, it is used by the U.S. Immigration and Customs Enforcement Agency.

The Steyr AUG was designed as a family of rifles that could readily be adapted to varying roles by changing the barrel length. Examples include a compact length of 13.8 inches; a 16-inch carbine barrel; a 20-inch standard rifle barrel and a 24.4-inch light machine gun barrel. It has seen combat in East Timor, Afghanistan and Iraq.

AUG weights (unloaded) vary from standard rifle (7.9 pounds), carbine (7.3 pounds), sub-carbine (7.1 pounds), and submachine gun (7.3 pounds) to light machinegun (8.6 pounds).

So too, AUG barrel length varies from standard rifle (31.1 inches), carbine (27.2 inches),sub-carbine (24.8 inches), and submachine gun (26.2 inches) to light machinegun (35.4 inches).

The Steyr AUG fires both 5.56x45mm NATO and 9x19mm Parabellum in SMG. Magazines include a 25- or 32-round, translucent double-column version molded from a durable, lightweight polymer. The AUG light machine gun magazine holds 42 rounds. The Steyr assault rifle is a gas-operated rotating bolt capable of a rate of fire of 680 to 850 rounds per minute. Effective range for the AUG is 328 feet (100 meters).

The AUG can be converted to either left or right hand use by swapping out the bolt and replacing the ejection port covers. A single fire version, the AUG P is available to civilian and law enforcement markets. That Steyr weapon has a shorter, 16-inch barrel and a modified bolt, carrier and trigger assembly, allowing only semi-automatic fire.