The 380 ACP (9x17mm for Automatic Colt Pistol) is a pistol calibre with a straight-walled rimless case specifically developed by John Moses Browning in 1908. This cartridge was initially designed for the 1908 Pocket semi-automatic Colt model without outside dog. It was very widely sold for numerous models. Since then, this cartridge has remained very popular and has mainly become a reference for small defence weaponry. The 380 ACP calibre cartridge is still widely used with numerous hand guns of recent manufacture, even though it is not used as standard ammunition. This calibre is subject to specific CIP approval; it should not be confused with other calibres such as the .38 ACP (9x23mm), the 9mm Makarov (9x18mm), the 9mm Ultra (9x18mm Ultra), or the 9mm Parabellum (9x19mm), with which it is absolutely not interchangeable. When shot from guns without cylinder head locking, the 380 ACP calibre cartridge generally gives very good accuracy because the barrel remains attached to the body of the weapon, and this prevents the breech from unlocking. The 380 ACP has quite a low level of recoil for an ammunition that has nevertheless a good level of performance; the bullets used generally have a mass ranging from 5.50 to 6.15 grammes for speeds varying from 275 to 310 m/s according to barrel length. Winchester offers a 380 Auto calibre load with a 6.16 gramme (95 grains) FMJ bullet with a speed of 291 m/s.