A .380 ACP pistol cartridge by Sellier & Bellot.
|Place of origin||United States|
|Manufacturer||Colt's Manufacturing Company|
|Case type||Rimless, straight|
|Bullet diameter||.355 in (9.0 mm)|
|Neck diameter||.373 in (9.5 mm)|
|Base diameter||.374 in (9.5 mm)|
|Rim diameter||.374 in (9.5 mm)|
|Rim thickness||.045 in (1.1 mm)|
|Case length||.680 in (17.3 mm)|
|Overall length||.984 in (25.0 mm)|
|Maximum pressure||21,500 psi (148 MPa)|
|Test barrel length: 3.75 inches (9.5 cm)
Source(s): Federal Cartridge 
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.
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 guns, such as the Ingram MAC-11 and vz. 83.
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.
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 115 grains (7.5 g), 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 PICO .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, Kahr CW380, Ruger LCP, Ruger LC380 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 190 to 220 foot-pounds force (260 to 300 J). The table below shows common performance parameters for several .380 ACP loads. Bullet weights ranging from 85 to 95 grains (5.5 to 6.2 g) are common. Penetration depths from 6.5 to 17 inches (16.5 to 43.2 cm) are available for various applications and risk assessments.
|Manufacturer||Load||Mass||Velocity||Energy||Expansion (inches)||Penetration ||PC||TSC|
|ATOMIC Ammo||Bonded JHP||90 gr (5.8 g)||1,100 ft/s (340 m/s)||241 foot-pounds force (327 J)||0.64 inches (16.3 mm)||12.0 inches (304.8 mm)||NA||NA|
|Cor-Bon||JHP +P||90 gr (5.8 g)||1,050 ft/s (320 m/s)||220 foot-pounds force (300 J)||0.58 inches (14.7 mm)||9.0 inches (228.6 mm)||2.38 cubic inches (39.0 cm3)||15.7 cubic inches (257 cm3)|
|Federal||HydraShok JHP||90 gr (5.8 g)||1,000 ft/s (300 m/s)||200 foot-pounds force (270 J)||0.58 inches (14.7 mm)||10.5 inches (266.7 mm)||2.77 cubic inches (45.4 cm3)||21.0 cubic inches (344 cm3)|
|Winchester||Silvertip JHP||85 gr (5.5 g)||1,000 ft/s (300 m/s)||189 foot-pounds force (256 J)||0.63 inches (16.0 mm)||6.5 inches (165.1 mm)||2.03 cubic inches (33.3 cm3)||10.6 cubic inches (174 cm3)|
|CCI/Speer||JHP||88 gr (5.7 g)||1,000 ft/s (300 m/s)||196 foot-pounds force (266 J)||0.36 inches (9.1 mm)||17.0 inches (431.8 mm)||1.73 cubic inches (28.3 cm3)||9.1 cubic inches (149 cm3)|
|Hornady||XTP||90 gr (5.8 g)||1,000 ft/s (300 m/s)||200 foot-pounds force (270 J)||0.44 inches (11.2 mm)||11.8 inches (299.7 mm)||1.73 cubic inches (28.3 cm3)||9.1 cubic inches (149 cm3)|
|Federal||FMJ||95 gr (6.2 g)||955 ft/s (291 m/s)||193 foot-pounds force (262 J)||0.36 inches (9.1 mm)||17 inches (431.8 mm)||1.73 cubic inches (28.3 cm3)||8.7 cubic inches (143 cm3)|
- Expansion – expanded bullet diameter (ballistic gelatin).
- Penetration – penetration depth (ballistic gelatin).
- PC – permanent cavity volume (ballistic gelatin, FBI method).
- TSC – temporary stretch cavity volume (ballistic gelatin).
- .380 Auto
- 9mm Browning
- 9mm Browning Short
- 9mm Corto
- 9mm Court
- 9mm Kratak
- Kratka 9 (Devetka)
- 9mm Kurz
- 9mm Scurt
- 9mm Short
- "Federal Cartridge Ballistics". Archived from the original on 27 September 2007. Retrieved 2007-09-25.
- Wilson, R. K. Textbook of Automatic Pistols, p.241. Plantersville, SC: Small Arms Technical Publishing Company, 1943.
- "Ingram MAC Model 10 / M10 and Model 11 / M11 submachine guns (USA)". Archived from the original on 29 September 2007. Retrieved 2007-09-25.
- Jones, Richard (2009). Jane's Infantry Weapons 2009-2010. Jane's Information Group. p. 107. ISBN 0-7106-2869-2.
- ".380ACP Terminal Ballistics". Archived from the original on 16 October 2007. Retrieved 2007-09-25.
- Ayoob, Massad. (2007)The Gun Digest Book of Combat Handgunnery. Krause Publications. Page 97. ISBN 0-89689-525-4.
- Marshall and Sanow, Street Stoppers, Appendix A, Paladin 2006 ISBN 978-0-87364-872-1
- Colt Automatic Pistols Website
- Article on Defensive Use of .380 ACP from American Rifleman
- StoppingPower.Info .380 ACP vs various target videos
- Ballistics By The Inch .380 ACP Results.
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