.32 ACP

The .32 ACP is a semi-rimmed, straight-walled pistol cartridge John Browning designed for Fabrique Nationale in 1899, first chambered in the FN Model 1900. It was among the earliest commercially successful self-loading pistol cartridges: small enough for a compact blowback pocket pistol, yet reliable enough for the police and military service pistols that adopted it across Europe through both world wars, under its metric name of 7.65×17mm Browning.

At 17.2 mm case length and a 160 MPa C.I.P. pressure ceiling, it is a low-pressure round by the standards of a modern service pistol, which is exactly what let it run in simple, unlocked blowback actions with no rotating barrel or locking lugs. That combination — light recoil, a slim single-stack magazine, and a mechanism cheap to manufacture — made it the standard chambering for small European and American pocket autos for most of the twentieth century, a role now mostly filled by 9×19mm and .380 ACP subcompacts.

This entry carries the full C.I.P. dimensional standard and one factory load, Federal’s American Eagle 71-grain full metal jacket rated at 274.3 m/s from a stated 4-inch test barrel. No free source publishes a rifling twist rate tied specifically to a commercial pocket-pistol barrel, and no ballistic coefficient for the round-nose FMJ bullet shown was found published anywhere free — the cartridge computes a muzzle energy figure but no trajectory.