The AUG is an Austrian bullpup 5.56mm assault rifle, designed in the early 1970s by Steyr Mannlicher GmbH & Co KG (formerly Steyr-Daimler-Puch). The AUG (Armee Universal Gewehr—”universal army rifle”) was adopted by the Austrian Army as the StG 77 (Sturmgewehr 77) in 1977, where it replaced the 7.62mm StG 58 automatic rifle (a license-built FN FAL). In production since 1978, it is the standard small arm of the Austrian Bundesheer and various national police units.
The rifle has also been adopted by the armed forces of Argentina, Australia (accepted into service in 1985 and manufactured by Australian Defence Industries in Lithgow), this F88 Austeyr model is also in use by New Zealand, Bolivia, Ecuador (since 1988), Republic of Ireland, Luxembourg, Saudi Arabia, Tunisia (introduced in 1978), Pakistan, and (since 1988) U.S. Customs Service (now the U.S. Immigration and Customs Enforcement agency).
AUG A3: Similar to the AUG A2, but features a MIL-STD-1913 rail on top of the receiver, and an external bolt release.