.25 ACP

.25 ACP
.25 ACP cartridge with scale
Type	Pistol
Country of Origin	USA
Specifications
Case Type	Semi-rimmed, straight
Bullet Ø	.251 in (6.4 mm)
Neck Ø	.276 in (7.0 mm)
Base Ø	.277 in (7.0 mm)
Rim Ø	.298 in (7.6 mm)
Case Length	.62 in (16 mm)
Full Length	.91 in (23 mm)
Rifling twist	1:16
Primer	Small pistol
Production & Service
Designer	John Browning
Design Date	1906
Ballistic Performance Sampling
Bullet Wt./type Velocity Energy 35 gr (2.3 g) Safety 1,150 ft/s (350 m/s) 103 ft·lbf (140 J) 35 gr (2.3 g) JHP 900 ft/s (270 m/s) 63 ft·lbf (85 J) 45 gr (2.9 g) JHP 815 ft/s (248 m/s) 66 ft·lbf (89 J) 50 gr (3.2 g) FMJ 760 ft/s (230 m/s) 65 ft·lbf (88 J) Test barrel length: 2 in Source: Guns & Ammo Magazine

The .25 ACP (Automatic Colt Pistol) (6.35x16mmSR) centerfire pistol cartridge is a semi-rimmed, straight-walled pistol cartridge designed by John Browning in 1906.

Design

Dimensions for the .25 ACP cartridge

The cartridge was designed for early blowback pistols that lacked a breech locking mechanism. The cartridge is of semi-rimmed design meaning that the rim protrudes slightly beyond the diameter of the base of the cartridge. A recessed extractor groove allows an extractor to grab the cartridge reliably. It is the smallest centerfire pistol round in production, and is commonly chambered in small, so-called "vest pocket" pistols. A line of revolvers produced by the German firm Decker were chambered for this cartridge [1]. However it is probably most popular due to use in the Colt Model 1908 Vest Pocket and the Raven MP-25.

Performance

The use of the .25 ACP allows for a very compact lightweight gun, but the cartridge is short ranged with regards to power, putting it in the same class as the .22 LR rimfire cartridge. Although the .22 is slightly more powerful when fired from equal length short barrels, the .25 ACP is viewed by many as a better choice for personal defense due to its more reliable semi-rimmed centerfire case design. Manufacturers have loaded commercial hollow point bullets to higher velocities than the standard 50-grain (3.2 g) FMJ load. Both rounds certainly pose an effective psychological threat against attackers not armed with a firearm. Firearms chambered for the .25 ACP cartridge run the gamut from very cheaply made guns like the Raven MP-25 to very well made and relatively expensive guns like the Baby Browning or Beretta Bobcat. The tiny cartridge has also been used in some precision crafted target pistols.

Browning "Baby"

Synonyms

• 25 Auto
• .25 Auto
• 6.35 mm
• 6.35 mm Browning
• 6.35x16mmSR

See also

• List of firearms
• List of handgun cartridges
• 6 mm caliber

References

• Pistol case specifications
• Guns & Ammo Magazine ballistics database
• The Reload Bench: .25ACP