In 1947, the US Army Air Corps (it had not yet become the Air Force) was assessing its pilot survival equipment, and decided that it wanted a smaller and lighter handgun than the Colt 1911. It put forth a tender for new designs in .30 to .35 caliber, and two companies were chosen to produce prototypes. These were Colt and High Standard, and today's pistol is one of the High Standard guns.
Designated the T3, High Standard made three batches of four guns each, for a total of 12. The first and last batches used single stack magazines and the second batch used double stack Browning High Power magazines, but they were all aluminum-framed guns chambered for 9x19mm. The Army Air Corps wanted simple blowback actions, noting on the tender that the Beretta 1923, Astra 400, and Walther MP all demonstrating that a blowback 9x19 handgun was feasible. High Standard complied, but also submitted barrels for the guns which used an interesting delaying system which consisted of rings cut in the chambers. Brass cartridge cases would expand into these rings upon firing, thus requiring addition time and energy to force the cases to extract, thus delaying the opening of the slide.
Ultimately in 1953 the project was cancelled, as the pistols all showed significant frame damage - the aluminum alloy was just not compatible with the high slide velocity that was the natural consequence of the unlocked action. However, it is very interesting to note the number of notable firearms designers involved in the project - George Wilson, Robert Hillberg, and Ott-Helmuth von Lossnitzer among them.
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