The history and development of the 32 ACP begins about 1896 with John Browning and the 32 S&W revolver cartridge. In 1896 Browning adapted his first blowback design into a pocket-sized striker-fired pistol.

In August 1896 Browning sent modified 32 S&W cases to Winchester for a sample lot to be produced. In 1897 the prototype pistol and about 500 experimental cartridges were sent to FN, where the pistol and ammunition worked flawlessly. FN immediately began setting up production and released the pistol and cartridge for commercial sales in 1899.

The initial cartridges made by Winchester, internally designated as 32 S&W Rimless, had a case length of 15.4mm and a rim diameter of .3565″. During development with FN the case was lengthened to 17mm and the rim made slightly smaller at .353″. In 1899 UMC began producing the cartridge for the South American market under the name 32 Browning. In Europe it was known as 7.65mm Browning.

In 1902, while Colt was beginning production of the 1903 Pocket Hammerless pistol, UMC and Winchester standardized case dimensions so the cartridge would work in both FN and Colt pistols. When Colt began sales of the Pocket Hammerless pistol the cartridge designation for the American market was changed to 32 ACP.

Throughout production minor changes and variations were made, but little development has taken place since the bullet diameter was standardized at .311″-.312″ in 1912. While the cartridge has now largely fallen out of popularity in favor of larger higher pressure rounds, the millions of pistols chambered for the 32 ACP have insured that the cartridge will be produced for many years to come.