When the United States entered World War One, it had a significant shortfall in military handguns. The M1911 pistol production was expanded as much as possible, but more guns were needed. Both Colt and Smith & Wesson adapted revolver designs to Army standard .45 ACP ammunition, and both were accepted into service as the M1917, despite being different guns with no interchangeable parts.
The most interesting mechanical element of the M1917 is the development of half-moon clips to allow easy extraction of the rimless .45 cartridge. The clips were designed by S&W, but also licensed to Colt for use in their M1917 revolvers as well.
The S&W M1917 began as Smith & Wesson’s Triple Lock design, which was simplified a bit (by removing the cylinder crane lock and the barrel lug) and rechambered for .455 Webley to sell to British and Canadian forces before the US entered the war. About 75,000 were sold like this, and it was then rechamberewd again for .45 ACP for US military sales. The first US deliveries were made in October 1917, and about 163,000 were produced by the time production ended in 1919. Only about half of them actually got to the front lines by the end of the war, and many of the guns went into storage. They were actually brought back out and used in significant use in World War Two as well.
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