. 380 ACP The . 380 ACP ( Automatic Colt Pistol ) pistol cartridge is a rimless , straight - walled pistol cartridge developed by firearms designer John Browning . The cartridge headspaces on the mouth of the case . It was introduced in 1908 by Colt , and has been a popular self - defense cartridge ever since . Other names for . 380 ACP include . 380 Auto , 9mm Browning , 9mm Corto , 9mm Kurz , 9mm Short , 9×17mm and 9 mm Browning corto ( which is the CIP designation ) . It is not to be confused with . 38 ACP , 9mm Makarov or 9mm Luger . Design . The . 380 ACP cartridge was designed for early blowback pistols which lacked a barrel locking mechanism . The locking mechanism that is found on most other pistols is not necessary for the . 380 because of the round ' s relatively weak bolt thrust when fired . The recoil spring and the mass of the slide are enough to buffer the recoil energy of the round . This simplifies manufacture of pistols chambered for such a round , generally thereby lowering the cost . It also permits the barrel to be permanently fixed to the frame , which promotes accuracy . There have , however , been a number of locked - breech pistols chambered in . 380 ACP . There have also been some diminutive submachine gun s , such as the Ingram MAC - 11 and vz . 83 . Uses . The . 380 ACP has experienced widespread use in the years since its introduction . It was famously used by many German officers during World War II in the Walther PPK , as well as by Italian forces in the Beretta M1934 . However , as a service pistol round , its power did not provide suitable penetration for combat . It did find use as a backup gun due to low recoil , and is popular in the civilian market as a personal defense round . The . 380 ACP round is considered suitable for self - defense situations , and as a result , it has been a viable choice for concealed carry pistols . The combination of decent penetration in close range defense situations with light recoil has made it a viable round for those who wish to carry a small , lightweight handgun that can still provide adequate defense . It was the round used in Defense Distributed ' s " Wiki Weapon " project to successfully 3D print a firearm . Performance . The . 380 ACP is compact and light , but has a relatively short range and less stopping power than other modern pistol cartridges . According to gun author Massad Ayoob , " Some experts will say it ' s barely adequate , and others will say it ' s barely inadequate . " Even so , it remains a popular self - defense cartridge for shooters who want a lightweight pistol with manageable recoil . It is slightly less powerful than a standard - pressure . 38 Special and uses 9 mm ( . 355 in ) diameter bullets . The heaviest bullet that can be safely loaded into the . 380 ACP is , though the standard has long been 85 , 90 or 95 grains ( 5 . 5 , 5 . 8 or 6 . 2 g ) . The . 380 has had something of a recent upsurge in popularity with the increase of concealed carry laws , as have the compact and inexpensive pistols that make use of it . Popular pistols chambered in . 380 ACP include the Colt Mustang pocketlite , Llama Firearms Micromax , SIG Sauer P238 , Beretta . 380 , Walther PPK / S , Walther PK380 , Bersa Thunder 380 , CZ 83 , SIG Sauer P230 / P232 , Kel - Tec P - 3AT , Smith & Wesson Bodyguard 380 , Diamondback DB380 , Kahr P380 , Ruger LCP and Taurus TCP 738 . Glock also produces models in . 380 , though they are not available to the U . S . market because they do not earn enough " points " for importation under Federal law . The wounding potential of bullets is often characterized in terms of a bullet ' s expanded diameter , penetration depth , and energy . Bullet energy for . 380 ACP loads varies from roughly . The table below shows common performance parameters for several . 380 ACP loads . Bullet weights ranging from are common . Penetration depths from are available for various applications and risk assessments . " Key : "