.25 ACP [SEP] designer
.25 ACP
The .25 ACP (Automatic Colt Pistol) (6.35×16mmSR) is a semi-rimmed, straight-walled centerfire pistol cartridge introduced by John Browning in 1905 alongside the Fabrique Nationale M1905 pistol.
Design.
The cartridge was designed by John Browning for early blowback pistols that lacked a breech locking mechanism. The cartridge was designed to duplicate the performance of a .22 Long Rifle cartridge, when fired from a two-inch barrel. The .25 caliber was the smallest case Browning could use that still had space for
.400 Cor-Bon
The .400 Corbon is an automatic pistol cartridge developed by Cor-Bon in 1997. It was created to mimic the ballistics of the 10 mm Auto cartridge in a .45 ACP form factor.
It is essentially a .45 ACP case, necked down to .40 caliber with a 25-degree shoulder.
History and design.
Peter Pi, founder of Cor-Bon and the designer of the cartridge, explained his reason for developing the cartridge: "Velocity is the key to making hollowpoint bullets work.