.32 ACP (Automatic Colt Pistol), also known as the .32 Automatic is a centerfire pistol cartridge. It is a semi-rimmed, straight-walled cartridge developed by firearms designer John Browning, initially for use in the FN M1900 semi-automatic pistol. It was introduced in 1899 by Fabrique Nationale, and is also known as the 7.65×17mm Browning SR or 7.65 mm Browning
John Browning engineered a number of modern semi-automatic pistol mechanisms and cartridges. As his first pistol cartridge, the .32 ACP needed a straight wall for reliable blowback operation as well as a small rim for reliable feeding from a box magazine. The cartridge headspaces on the rim. The cartridge was a success and was adopted by dozens of countries and countless governmental agencies.
When the .32 ACP cartridge was introduced, it was chambered in a variety of popular blowback automatic pistols of the day, including the Colt Model 1903 Pocket Hammerless, the Savage Model 1907 Automatic Pistol, and the Browning Model 1910 Automatic Pistol. The .32 ACP has been chambered in more handguns than any other cartridge. Between 1899 and 1909, Fabrique Nationale produced 500,000 guns chambered for .32 ACP.
Adolf Hitler was believed to have committed suicide with his personal .32 ACP Walther PPK, by pressing it against his right temple and pulling the trigger while simultaneously biting down on a cyanide capsule.
The popularity of the .32 ACP in the mid 20th century cannot be overstated—especially in Europe. Firearms expert Geoffrey Boothroyd of the UK informed author Ian Fleming, his countryman, that James Bond's side arm should be a Walther PPK chambered in .32 ACP. A significant factor in recommending this round was its near universal availability throughout the world in the 1950s.
Heckler & Koch produced the HK 4, their first handgun, in 1967. Twelve thousand HK 4 pistols were produced in .32 ACP for the German police and other government agencies.