The Hammond automatic pistol is a prototype American pistol.
Grant Hammond filed a patent for his original design, a .32 ACP pistol, in 1913; however, as somewhat hinted by the date he filed his patent, his pistol was way too late to be able to take part in the 1907 US Pistol & Revolver Trials. Instead, he presented his pistol proactively to the US Military in 1917 or 1918, in the hopes of it being accepted and used as a weapon that could supplement or even possibly replace the M1911 pistol. While the weapon proved to be quite accurate, it was deemed not reliable or durable enough for actual serious adoption, and as such, was rejected.
Hammond's original .32 ACP pistol used a ridiculously complicated hybrid blowback-blow forward system; this was massively simplified with the submission of the .45 ACP pistol, which used a standard short-recoil system with a tilting breechblock.