.380 Auto (aka 380 ACP 9x17 9mm Kurz 9mm Browning) was developed in 1908 by John Browning for the 1908 hammerless semi-automatic pistol. - Today .380 Auto is one of the most popular personal defense rounds due to its smaller size and the ability to fit in a smaller pistol profile. - Ballistic Coefficient (G1): 100 - Muzzle Velocity V0 ft/sec: 1033 - Muzzle Energy E0 J ft/lb: 223 - Max Powder Pressure Bar (lb/inch2): 18130 - Cartridge Max Length: .98 inches - Cartridge Average Weight: 143 grains - Rounds per Box: 50