Steyr AUG

The Steyr AUG is an Austrian bullpup 5.56×45mm NATO assault rifle, designed in the 1960s 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 1978, where it replaced the 7.62×51mm StG 58 automatic rifle (a licence-built FN FAL). In production since 1978, it is the standard small arm of the Austrian Bundesheer and various national police units.

The AUG and its variants have also been adopted by the armed forces of Argentina, Australia, Bolivia, Ecuador, Ireland, Luxembourg, Malaysia, New Zealand, Oman, Saudi Arabia, Tunisia, Pakistan, the Falkland Islands Defence Force and the U.S. Immigration and Customs Enforcement.

The Steyr AUG is a bullpup 5.56×45mm NATO automatic rifle. It is a selective-fire weapon with a conventional gas-piston-operated action that fires from a closed bolt. It is designed as a family of rifles that could be quickly adapted to a wide variety of roles with the change of the barrel to a desired length and profile.

The AUG is a modular configuration rifle that employs a high level of polymer and advanced alloy components. It is chambered in 5.56×45mm NATO cartridge and has the standard 1:9 rifling twist that will stabilize both SS109/M855 and M193 rounds. Some nations including Australia and New Zealand uses a version with a 1:7 twist optimized for the SS109 NATO round.

An improved variant of the AUG, the AUG A1 consists of six main assemblies: the barrel, receiver with integrated telescopic sight, bolt and carrier, trigger mechanism, stock and magazine.