Australian Austen Mk I 9 mm sub machine gun, 1942-1945 (c); with bakelite grips and camouflaged with green paint. In 1941 Australia possessed no home manufactured sub-machine gun although the Owen SMG was in the initial stages of production. The Australians therefore produced a modified Sten with a mainspring, bolt and folding butt derived from the German MP40 weapon, the Austen (Australian Sten).