Evelyn Owen, an Australian, developed his first automatic weapon, chambered for .22LR cartridge, by 1939, and offered it to Australian army. This weapon was a strange-looking revolver-type contraption with fixed "cylinder" instead of magazine, and thumb-operated trigger. However, by 1940 Owen produced its next design, in somewhat more potent (but still relatively mild) .32ACP / 7.65x17 Browning cartridge. This was more "usual" weapon, with traditional trigger, dual pistol grips and detachable box magazine, inserted under the receiver and inclined rearward and to the left. By 1941, Owen produced several more prototypes, chambered in .45ACP, 9mm Luger and even .38 Special revolver cartridges; this work was done at Lysaghts Newcastle Works in New South Wales, Australia. 9mm prototype, made by Lysaghts, was tested against Thompson and Sten submachine guns, and found superior to both. Adopted in 1942, this gun was manufactured until 1945 in three basic versions, Mark 1-42, Mark 1-43 (or Mark 1 Wood butt), and Mark 2. About 45 000 Owen SMGs were made by Lysaghts, and these remained in service with Australian forces until 1960s, through World War 2, Korean and Vietnam wars. In general, these weapons were well liked by soldiers due to their robustness, reliability and simplicity. The only downside of Owen SMG was its somewhat heavy weight.
Owen submachine guns are blowback operated, top-fed weapons that fired from open bolt. Receiver is of tubular shape, with the bolt body separated from the cocking handle by the small bulkhead inside. This precluded the dirt to enter the receiver area through the cocking handle slot, but also required the barrel to be made removable, as the bolt and return spring were pulled forward out of receiver. Barrel was held in place by simple latch, located at the front of the receiver, ahead of the magazine housing. Muzzle was equipped with recoil compensator. Pistol grips were made from wood, detachable buttstock was made of steel wire on Mk.1-42 Owens and from wood on later models. Due to the top mounted magazine, fixed sights were offset to the left.