.45 ACP

The .45 ACP (Automatic Colt Pistol) pistol cartridge was designed by firearms designer John Browning. Based upon his earlier .380 ACP pistol cartridge, the .45 ACP was introduced along with Colt M1911 pistol adopted by the US Army in 1911. The round was later used in several submachine guns.

Contents
1 Design
2 Performance

2.1 Muzzle velocity

3 Variants
4 Synonyms
5 Weapons using the .45 ACP
6 See also
7 External links

Design

The US Cavalry, based on testing in battle, decided that existing .38 caliber pistol cartridges appearing in the early 1900s were not adequate enough to replace the current cavalry revolver, a .45 Colt Single Action Army. The US Cavalry demanded stopping power similar to the .45 Colt cartridge (sometimes erroneously called the ".45 Long Colt"). Colt had been working with Browning on a .41 caliber cartridge in 1904, and in 1905 when the Cavalry asked for a .45 caliber equivalent, Colt modified the pistol design to fire a .45 caliber version of the prototypical .41 caliber round. The original round that passed the testing fired a 200 grain (13 g) bullet at 900 ft/s (275 m/s), but was later changed to a 230 grain (15 g) bullet at about 850 ft/s (260 m/s). The resulting .45 ACP cartridge is similar in performance to the .45 S&W cartridge, and thus slightly less powerful than the .45 Colt cartridge.

Performance

The result is one of the world's most effective combat pistol cartridges, one that combines very good accuracy with ample stopping power for use against human assailants. However the .45 ACP has disadvantages as a combat round. It is a low-velocity round, and thus not effective against body armour. The rounds lack accuracy or velocity at long range. Another drawback is the bullet's large size and greater material costs in manufacturing compared to the 9 mm Luger cartridge.

Even in its full metal jacket form the .45 ACP cartridge is very effective against targets that do not wear body armour, because the large bullet has a tendency to expand when it hits bone. Hollow-point configurations increase the expansion and flesh-cutting potential of the round.

The .45 ACP bullets have little tendency to overpenetrate, which otherwise results when a projectile passes through an intended target with enough velocity to injure another person. The combination of stopping power and controlled penetration makes the .45 ACP practical for police use. Many US hostage rescue teams prefer the .45 ACP because of these qualities.

Today most of the US military uses the 9 mm Luger cartridge, but the accuracy of the .45 ACP cartridge has maintained its popularity with large caliber sport shooters. Many US Special forces and police units (such as SFOD-D, more commonly known as Delta Force) still use this round in the form of modified 1911A1s and Heckler und Koch SOCOM Mk. 23s and USP Tacticals.

Muzzle velocity

+ P loads

Variants

Several manufacturers market pre-loaded .45 ACP rounds in sizes ranging from 117 to 230 grains (8 to 15 g), with the most popular commercial load being the standard military loading of a 230 grain (15 g) FMJ bullet at around 850 f/s (260 m/s). Specialty rounds are available in weights under 100 grains (6.5 g) and over 260 grains (16.8 g); the most popular round among reloaders and target shooters is the original 200 grain (13 g) bullet. Combat rounds sold under such names as "Hydra-shok" are made with hollow points and partial metal jackets designed to spread upon impact with soft tissue, both increasing the energy transferred from the round to the target and enhancing the cutting power of the expanded round. Some hollow-point ACP rounds are legally available only to qualified law enforcement purchasers.

Synonyms

Weapons using the .45 ACP

See also

External links

See also: .45 ACP, .380 ACP, .45 Colt, 1900s, 9 mm Luger, Body armour, Cartridge (weaponry), Colt Firearms, De Lisle carbine, FP-45 Liberator