.25 ACP

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.25 ACP
.25 ACP cartridge with scale
Place of originUnited States and Belgium
Production history
DesignerJohn Browning
Case typeSemi-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 twist1:16
Primer typeSmall pistol
Maximum pressure25,000 psi (170 MPa)
Maximum CUP25,000[1] CUP
Ballistic performance
Bullet mass/type Velocity Energy
35 gr (2 g) JHP 900 ft/s (270 m/s) 63 ft⋅lbf (85 J)
45 gr (3 g) JHP 815 ft/s (248 m/s) 66 ft⋅lbf (89 J)
50 gr (3 g) FMJ 760 ft/s (230 m/s) 65 ft⋅lbf (88 J)
Test barrel length: 2"
Source(s): Guns & Ammo Magazine

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.


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]

See also[edit]


  1. ^ Saami pressures. (n.d.). Retrieved May 3, 2023, from https://leverguns.com/articles/saami_pressures.htm
  2. ^ *Wilson, R. K. Textbook of Automatic Pistols. Plantersville, SC: Small Arms Technical Publishing Company, 1943. p. 258. ISBN 978-0-935632-89-7.
  3. ^ Hogg, Ian; Walter, John (2004-08-29). Pistols of the World. David & Charles. ISBN 0873494601.
  4. ^ Bowen, Hamilton. The Custom Revolver. Privately printed, 2001. ISBN 978-0-9713366-0-5.
  5. ^ Jerry Ahern (2010), Gun Digest Buyer's Guide to Concealed-Carry Handguns, Gun Digest Books, pp. 19–20, ISBN 978-1-4402-1383-0

External links[edit]