The .25 ACP (Automatic Colt Pistol), also known as the .25 Auto, .25 Automatic, or 6.35×16mmSR) is a semi-rimmed, straight-walled centerfire pistol cartridge introduced by John Browning in 1905 alongside the Fabrique Nationale M1905 pistol.
.25 ACP | ||||||||||||||||
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Type | Pistol | |||||||||||||||
Place of origin | United States and Belgium | |||||||||||||||
Production history | ||||||||||||||||
Designer | John Browning | |||||||||||||||
Designed | 1905 | |||||||||||||||
Produced | 1905–present | |||||||||||||||
Specifications | ||||||||||||||||
Case type | Semi-rimmed, straight | |||||||||||||||
Bullet diameter | .2512 in (6.38 mm) | |||||||||||||||
Land diameter | .2429 in (6.17 mm) | |||||||||||||||
Neck diameter | .276 in (7.0 mm) | |||||||||||||||
Base diameter | .278 in (7.1 mm) | |||||||||||||||
Rim diameter | .302 in (7.7 mm) | |||||||||||||||
Rim thickness | .043 in (1.1 mm) | |||||||||||||||
Case length | .615 in (15.6 mm) | |||||||||||||||
Overall length | .910 in (23.1 mm) | |||||||||||||||
Rifling twist | 1:16 | |||||||||||||||
Primer type | Small pistol | |||||||||||||||
Maximum pressure | 25,000 psi (170 MPa) | |||||||||||||||
Maximum CUP | 25,000[1] CUP | |||||||||||||||
Ballistic performance | ||||||||||||||||
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Test barrel length: 2" Source(s): Guns & Ammo Magazine |
The cartridge is of semi-rimmed design meaning that the rim protrudes slightly beyond the diameter of the base of the cartridge so the cartridge can headspace on the rim.[2]
Though the .25 ACP was designed for semi-automatic pistols, various .25 ACP revolvers were produced in the early twentieth century by Belgian, French, and German gunmakers such as Adolph Frank and Decker.[3] In the late twentieth century, Bowen Classic Arms produced a custom Smith & Wesson revolver in .25 ACP.[4]
The use of the .25 ACP allows for a very compact lightweight gun, usually pocket pistol. With quality ammo available on the market, the .25 ACP is viewed by some[who?] as a solid choice for personal defense handguns due to its centerfire-case design, which is inherently more reliable than a .22 LR rimfire cartridge.[5]