.380 ACP

The .380 ACP (Automatic Colt Pistol) is a rimless, straight-walled pistol cartridge developed by firearms designer John Moses Browning. The cartridge headspaces on the mouth of the case. It was introduced in 1908 by Colt, for use in its new Colt Model 1908 pocket hammerless semi-automatic, and has been a popular self-defense cartridge ever since, seeing wide use in numerous handguns (typically smaller weapons). Other names for .380 ACP include .380 Auto, 9mm Browning, 9mm Corto, 9mm Kurz, 9mm Short, 9×17mm and 9 mm Browning Court (which is the C.I.P. designation). It is not to be confused with .38 ACP, 9mm Ultra, 9mm Makarov or 9mm Parabellum.

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.25 ACP

The .25 ACP (Automatic Colt Pistol) (6.35×16mmSR) is a semi-rimmed, straight-walled centerfire pistol cartridge introduced by John Browning in 1905 alongside the Fabrique Nationale M1905 pistol. In more recent years, most pistols available in .25 ACP are also available in a more effective caliber.

Design

The cartridge was designed by John Browning for early blowback pistols that lacked a breech locking mechanism. The cartridge was designed to duplicate the performance of a .22 Long Rifle cartridge, when fired from a 2" barrel. The .25 caliber was the smallest case Browning could use, and utilize primer pocket, and sufficient rim. The greased, coated lead bullet design, standard for the .22 long rifle of the day, was replaced with a copper jacketed round nose profile for more reliable feeding in auto loading pistols. The bullet weight was typically 50 grains, keeping with the sectional density of the 40 grain .22 caliber bullet. 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. 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. The .25 ACP achieved widespread use after Colt introduced the Browning-designed Fabrique 1905 vest pocket (sometimes referred to as 1906) to the United States as the Colt Model 1908 Vest Pocket.

.32 ACP

.32 ACP (Automatic Colt Pistol), also known as the .32 Automatic is a centerfire pistol cartridge. It is a semi-rimmed, straight-walled cartridge developed by firearms designer John Browning, initially for use in the FN M1900 semi-automatic pistol. It was introduced in 1899 by Fabrique Nationale, and is also known as the 7.65×17mm Browning SR or 7.65 mm Browning.

History

John Browning engineered a number of modern semi-automatic pistol mechanisms and cartridges. As his first pistol cartridge, the .32 ACP needed a straight wall for reliable blowback operation as well as a small rim for reliable feeding from a box magazine. The cartridge headspaces on the rim. The cartridge was a success and was adopted by dozens of countries and countless governmental agencies.

When the .32 ACP cartridge was introduced, it was chambered in a variety of popular blowback automatic pistols of the day, including the Colt Model 1903 Pocket Hammerless, the Savage Model 1907 Automatic Pistol, and the Browning Model 1910 Automatic Pistol. To avoid patent infringement John Pedersen designed the Remington Model 51 so as to not to rely on any other, thus the unique hesitation lock breech mechanism was developed. The .32 ACP has been chambered in more handguns than any other cartridge. Between 1899 and 1909, Fabrique Nationale produced 500,000 guns chambered for .32 ACP.