According to Wardell, the “ease of manufacture, simplicity, rapidity of dismantling, no sliding features … and reliability” were the gun’s attributes. When the Australian Army would not supply 10,000 rounds of .32-caliber ammunition for a test range firing demonstration, both Wardell and Owen rightfully suspected an element of resistance on the part of the army.
To overcome the “lack” of sufficient .32-caliber rounds, Lysaght Works persisted and built another Owen gun prototype in March 1941 that was chambered for .45-caliber Automatic Colt Pistol (ACP) bullets. The .45 ACP round had made the Thompson 1928A1 a formidable, short-range submachine gun with incredible stopping power. Lysaght had been assured that plenty of ammunition would be available this time. However, after a successful test firing, the Australian Army would only supply .455-caliber ammunition, suitable only for the Webley Revolver, rather than the necessary .45 ACP rounds.
Army officials cited a shortage of .45 ACP ammunition for this new SMG since stocks of the round were used for the Thompson SMG. Wardell’s comments on the Army’s obstructionism were quite vitriolic. It was only through his tenacity and direct approach to civilian authorities that the project had not been completely derailed. Some individuals with connections in the War Cabinet in Canberra, who had been present when Owen and Wardell had exhibited their .32- and .45-caliber prototypes, concurred with Wardell’s observation that the Owen gun would have already been manufactured and distributed to Australian troops if the Army had cooperated.
The Army bureaucrats continued their obstructionism, telling Lysaght to provide a sample gun that chambered a .38-caliber Smith & Wesson (S&W) round. The demand was disingenuous since neither ammunition nor a barrel was to be provided for factory use. Wardell made dutiful attempts at an Owen Gun Annex at the Lysaght Works to produce an Owen gun prototype utilizing the .38 S&W rimmed revolver round. Predictably, the prototype failed in testing in July 1941 because the .38-caliber cartridge was underpowered for use with a SMG.
By September 1941, Wardell was convinced that any acceptable Owen gun prototype would require a 9mm round. Privately, he seethed to Essington Lewis, Director-General of Munitions, “Almost to the day it is 12 months since your prompt action caused Owen to be transferred from the Infantry at Bathurst to the Inventions Board at Melbourne, and it is two years since the war began. The Army’s answer to the submachine gun problem has been … to delay in every way possible the production of an Owen gun for [lack of] suitable ammunition.”
Finally, within days of Wardell’s outburst, the Army Ministry surprisingly commented, “There appears to be marked hostility, verging on deliberate obstruction … concerning the Owen gun.” The manufacture of Owen guns in 9mm was approved on September 7, 1941, with the performance trials at the end of that month, albeit an incredibly short interval for Lysaght Works to rechamber the gun.
Despite this plan of action, some senior Army officers still were of the belief that the Owen gun would fail and that an Australian-manufactured Sten gun would stop production of the expensive Thompson SMG and curtail production of the Owen gun. The Australian need for 100,000 SMGs would have been satisfied by the Sten gun if it had been left to the discretion of certain high-ranking Australian Army officers. In September 1941, Maj. Gen. Milford, who was Captain Dyer’s senior officer, had approved of the production of an Australian Sten gun. Additionally, General Sir Thomas Blamey’s initial preference for an SMG was the Australian Austen weapon, which was soon overshadowed by the superior Owen with the former rarely being used. Blamey was to become the Allied Land Forces commander in the Southwest Pacific Area (SWPA) under MacArthur.
Rigorous testing of accuracy and mechanical functionality, using battle condition impediments such as sand being poured over the weapons and water and mud immersion, was conducted at Long Bay on September 29, 1941, comparing the Sten Mk 1 (9mm), the .45 ACP Thompson 1928A1, and both the 9mm and .45 ACP Owen versions. Dirt proved to be the nemesis of both the Thompson and Sten SMGs during the tests, and even Milford recognized that the Owen gun “continued to function satisfactorily when subjected to severe conditions … and had distinct possibilities as a suitable and efficient weapon.”
Endurance testing over several days, involving the continuous firing of almost 3,000 rounds of ammunition, showed the Owen and Thompson SMGs to be reliable; however, the Sten Mk I broke down several times. In tests conducted by the Lysaght Works, the American Winchester 9mm round seemed to feed the best and was more accurate than either British or Australian-manufactured bullets, much to the dismay of Australian Army officers.
After the Long Bay testing, an order for 2,000 Owen guns was placed by the Department of Munitions on October 3, 1941. It had become apparent to many that the Army had procrastinated unnecessarily due to bias, and this opinion eventually made it to many Australian newspapers and other periodicals.
Once accepted into service, production of the Owen SMG began initially in the Lysaght facilities. The production was augmented by the Lithgow Small Arms Factory. The full production rate was limited to 2,000 guns per month due to the constraints of a nascent Australian military-industrial infrastructure.
The Owen SMG was a simply designed weapon with basic construction, allowing for mass production that the developing Australian industrial infrastructure could deliver. Lysaghts’ 9mm Owen gun was adopted in 1942 and manufactured in three basic versions, Mk I-42 (with bent steel wire butt), Mk I-43 (or Mk I with a wooden butt); and a Mk II. The Mk II version was a simplified production version of the Mk I-43 but only appeared in prototype form by war’s end.
The Owen SMG had a rate of fire of 7,000 rounds per minute and weighed just under 9.3 pounds unloaded and 10.6 pounds loaded. Its overall length was 32.5 inches with a barrel length of just under 10 inches. The gun had a muzzle velocity of almost 1,400 feet per second and an effective range up to 220 yards. There were also rear and forward pistol grips, both made of wood, for a firm two-point hold that incorporated finger grooves to improve stabilization of the gun platform. Additionally, the barrel was designed to be changed quickly, which would prove useful under rare circumstances when the gun was fired in a sustained fashion.
The only downside to the Owen SMG was its somewhat heavy weight; however, a sure two-hand hold on the pistol grips and use of the shoulder stock helped to balance this shortcoming. During the war, the average cost to manufacture the Owen SMG was approximately $30.
From a gun design standpoint, the Owen was essentially a typical “blowback” system utilizing a tubular, featureless receiver with an open bolt capped by a removable barrel assembly. Initially, the stock was skeletal to keep the weight down. The lower portion of the two-chamber receiver was hollowed out and a simple wooden pistol grip and trigger were affixed. The magazine feed was set across the forward upper end of the tubular receiver and vertically springloaded in a detachable, 32-round box magazine.
The top-mounted magazine required the iron sights to be offset to the side slightly, but it made no major impact on shooting since the Owen SMG was often fired from the hip. The magazine design also made for a reliable feed aided by both the magazine spring mechanism and gravity. Since the cartridge ejection port was on the bottom of the receiver tube, dirt that might enter from the magazine would often fall straight through, having no place to collect, which made it ideal for jungle fighting. Also, the top-loading box magazine and catch design allowed for a faster magazine change.
The Owen gun was resistant to fouling from dirt and mud. Its front-loading bolt and return spring, which was on a round piston, moved forward and backward in a separate compartment inside the receiver by means of a small bulkhead that isolated the small diameter bolt from its retracting cocking handle, effectively sealing the chamber, bolt, and spring area from the elements. Any dirt or mud that did get in was captured in areas machined on both ends of the bolt or was blown out through the bottom ejection port. Also, the gun had no sliding surfaces under heavy load. This design prevented dirt and mud from jamming the bolt.
Once deployed to the “diggers” fighting the Japanese, the weapon aptly proved its intrinsic value by withstanding the unforgiving nature of the jungle environment. The Owen SMG also sported various camouflage paint schemes to blend in with dense foliage. Some guns were fitted with short bayonets alongside the barrels since patrol action was often at close quarters and stealth was frequently required. The Owen’s rate of fire and reliable 32-round magazine made it formidable against fanatical Japanese banzai charges. The Owen SMG was further modified to take two magazines, a feature that would become quite common by 1945.