Mauser's classic early pocket pistol began as the model 1910, in .25 ACP caliber (6.35mm). It was then re-engineered for the larger .32 ACP (7.65mm) cartridge in 1914, and a final set of modifications too place in 1934. It is a simple blowback mechanism, with disassembly rather different from most other blowback pocket pistols.
