The .32 ACP (7.65×17mmSR) cartridge is a pistol cartridge.
The .32 ACP cartridge was famed gun designer John Browning's first cartridge, with most of his cartridge developments being for modern semi-automatic pistols. As it was Browning's first cartridge, it needed a straight wall for reliable blowback operation to occur, along with reliable small-rim feeding from box magazines. On its introduction, the cartridge was an immediate success and has since been used by many militaries and police forces over the past century, and was one of the most popular, if not the most popular cartridge in the first half of the 20th century. The .32 ACP cartridge has been chambered in more pistols than any other cartridge as a result of its popularity and near-universal availability. The cartridge is still used today, primarily in compact, inexpensive pistols and most modern Saturday night specials.
The .32 ACP round is a semi-rimmed, straight case centerfire cartridge meant for use with pistols. The design of the round is meant for blowback pistols which lack a breech-locking mechanism. Due to the somewhat low power and light weight of the bullet, Browning was able to practically use a blowback system in a small pocket pistol.
A compact and light cartridge, the .32 ACP round has been believed by many to be weak and lacking stopping power, but this has since been proven to not be the case. The light weight of the cartridges, along with the low recoil they produce and high accuracy roughly equal to that of higher caliber pistols makes them suitable calibers for firearms meant for concealed carry use. The .32 ACP cartridge offers more velocity than the .32 S&W cartridge, also a popular cartridge at the time. The .32 ACP cartridge is also used for veterinary "humane killers" due to its relatively low stopping power compared to other pistol cartridges.
The .32 ACP cartridge has gone by a wide variety of names, including:
- .32 Auto
- 7.65mm Browning
- 7.65×17mmSR (Short-Rimmed) Browning
- .32 Browning Auto
- 7.65mm Walther