The .25 ACP (Automatic Colt Pistol) was introduced by John Moses Browning in 1905. It was the smallest caliber that Browning could go while still retaining a centerfire primer pocket, which would be more reliable for self-defense than a rimfire primer. A Colt .25 Model 1908 Vest Pocket Pistol "pocket automatic" was recovered from Bonnie Parker's purse at the scene of her death in Louisiana after being by ambushed by the Texas Rangers in 1934.
The .32 ACP was John Browning's first pistol cartridge which debuted in 1899. The round was immediately popular worldwide but gained icon status in the 1950's when James Bond began neutralizing criminal masterminds, mad scientists, and psychopathic villains with his Walther PPK.
The .380 ACP is yet another one of John Browning's masterpieces and was released to the market in 1908. The infamous gangster John Dillinger who robbed 24 banks, 2 police stations, and escaped from prison twice, tried to pull a Colt Model 1908 Pocket Hammerless in .380 when he was gunned down by the FBI in Chicago in 1934 just 2 months after the takedown of Bonnie & Clyde. It was later adopted by the armies of at least five European nations as their standard pistol cartridge before World War II and was widely used by European police forces until the 1970s.