The Steyr AUG is the standard military weapon of its home country, Austria. It has also been adopted by armed forces of Argentina, Bolivia, Ecuador, Republic ofIreland, Luxembourg, Saudi-Arabia, Tunisia and Pakistan. It is also used by the U.S. Custom service. Also is version of it manufactured in Australia, and used by their and New Zealand's armed forces. The cartridge it uses, the 5.56x45mm NATO is one of the most used in the world.