AUSTEN submachine gun (machine carbine in contemporary terminology) was an urgent development, carried in Australia during earlier stages of World War 2 in the anticipation of possible Japanese invasion. It was based on British STEN submachine gun (the AUSTEN means Australian STEN), although some features (i.e. return spring guide, pistol grip and underfolding stock) were copied from the German MP40. About 20 thousands of AUSTEN Mk.1 submachine guns were manufactured during the WW2, but it was unable to achieve popularity of its main domestic rival, the Owen submachine gun, as the Owen was much more reliable, especially under the extreme environmental conditions of jungle warfare.
The AUSTEN submachine gun is a simple blowback weapon, firing from open bolt in semi-automatic or full automatic modes. The return spring is located insite the telescoping tubular guide, as in the German MP40. The fire mode selector is located on the right side of the trigger housing, above the trigger guard. The STEN-type box magazine is inserted horizontally from the left, ejection is to the right. AUSTEN submachine gun is equipped with two pistol grips and an underfolding metallic buttstock. The struts of the buttstock are hollow and hold inside a small screwdriver and a cleaning rod. The sights are of simple design, and not adjustable for range.