Introduced in 1905 by John Browning, the .25 Automatic Colt Pistol (ACP) cartridge was designed to be fired in the Fabrique Nationale Model 1905 pistol (6.35x16mmSR). This was a centerfire “vest pocket” pistol, designed for gentlemen who needed their firearms to remain undetectable. Among other bad press, some firearms authorities dismissed the small caliber as a "mouse gun." The .25 ACP is lethal, however, and firearms in this caliber should be treated with the same respect as larger caliber weapons.
Small, inexpensive firearms intended for concealed carry in a pocket or small handbag are the primary weapon chambered for .25 ACP. The .25 ACP enjoys several advantages as a concealed carry pistol. The pistol is small, making concealment much easier than with larger handguns in a variety of situations and locations . A standard size .25 ACP is smaller than even the smallest 9mm pistols. The .25 ACP is more reliable, with a centerfire primer, than .22 LR rimfire cartridges which are found in similar sized pistols. An abundance of self protection loads are available for the .25 ACP which maximize bullet penetration and expansion like a jacketed hollow point (JHP). The .25 ACP is worth consideration for self protection, especially with recent advancements in technology and design.
Many firearms have been chambered for the .25 ACP cartridge, including several revolvers. Many weapons that are now antiques were manufactured in Belgium or Italy, and can occasionally be found on firearms auction websites.The unique Lercker pistol was designed to fire the .25 ACP. It was fully automatic with a 20 round magazine, and it fired 1200 rounds per minute. It was not produced widely, yet this interesting pistol sheds new light on the .25 ACP as a self defense cartridge.
Firearms enthusiasts either love the .25 ACP cartridge, or hate it. There are enough fans in the firearms world that it has held its place. Manufacturers continue to produce firearms in this caliber, and it is included a subcompact option for many new pistols that are introduced. Ammo manufactures also continue to produce volumes of practice ammo and include it in their self defense product lines. The .25 ACP has mild recoil and shoots with acceptable accuracy and reliability. It will continue to be used for backup and deep concealment needs for a long time to come.