. 32 ACP . 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 . History . 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 . Design . The . 32 ACP was designed for blowback semi - automatic pistols which lacked a breech locking mechanism . The relatively low power and light bullet of the cartridge allowed Browning to incorporate a practical blowback mechanism in a small pocket - size pistol . It is still used today primarily in compact , inexpensive pistols . Cartridges in . 32 ACP are also sometimes used in caliber conversion sleeve s , also known as " supplemental chambers " , for providing an alternative pistol caliber carbine function in . 30 - caliber hunting rifles . Performance . The . 32 ACP is compact and light . While some believe it has marginal stopping power , it has been used effectively by military and police worldwide for the past century . Weapons chambered in it are often valued for their compactness . Although . 32 ACP handguns were traditionally made of steel , they have been produced in light weight polymers since the 1990s . Their light weight relative to larger caliber pistols make them sutiable for concealed carry use . It offers more velocity and energy than the . 32 S & W , which was a popular round for pocket defensive revolvers at the time of the . 32 ACP ' s development . Although of lighter bullet weight , the . 32 ACP also compares favorably to the . 32 S & W Long in performance . Some European 73 grain . 32 ACP loads provides similar performance to the . 32 H & R Magnum 77 grain lead flat point and 90 grain lead semiwadcutter . Even though the . 32 ACP is capable of killing small game , most handguns chambered for this round utilize fixed sights and are designed for use against human - sized targets at fairly close range , which greatly limits their utility as hunting handguns . The . 32 ACP is one of the most common calibers used in veterinary " humane killers " , such as the Greener Humane Killer . Given that a . 22 LR can penetrate bone , the higher power . 32 ACP can easily penetrate an animal skull with a muzzle - contact shot . As a result the round has been found to be perfectly adequate for the purpose , even where fully grown horses and bulls are concerned . In Europe , where the round is commonly known as the 7 . 65 mm Browning , the . 32 ACP has always been more widely accepted than it has in America , having a long history of use by civilians and police / security forces , along with limited issue by the military forces of some European nations . During the second half of the 20th century , several European countries developed firearms for police chambered in 9x18mm Makarov while chambering the same pistol for civilians in . 32 ACP and . 380 ACP . Examples include the Vz . 82 / CZ - 83 from Czechoslovakia , FEG PA - 63 / AP 765 from Hungary , SIG Sauer P230 from Switzerland , and P - 83 Wanad from Poland . Today the cartridge has an increased popularity in the United Sates due to modern compact concealed carry pistols chambered for it , such as the Kel - Tec P - 32 , Beretta Tomcat , Seecamp LWS 32 and North American Arms Guardian . 32 . This increase in popularity has led many ammunition manufacturers to develop new loads for the cartridge to increase performance . However , these polymer subcompact guns typically have barrel lengths around 2 . 5 " . The traditional steel guns chambered for . 32 ACP have barrel lengths around 3 . 5 " . Different barrel lengths can have a significant effect on bullet performance with longer barrels providing higher muzzle velocity and energy . For example , a Cor - Bon 60 grain . 32 ACP JHP has 130 ft • lbf of energy when fired out of a 2 . 5 " barrel and 165 ft • lbf of energy when fired out of a 3 . 5 " barrel . The shorter barrel length can also reduce the accuracy and range of a bullet .