This cartridge was developed by John Browning and was adopted by the United States Ordnance Department along with the Colt-Browning automatic pistol in 1911. It has also been made the official military handgun chambering by several other governments, notably Argentina, Mexico and Norway. The 45 Automatic is the most powerful military handgun cartridge in use today. This is a heavy and powerful sub-sonic round. Although its muzzle energy can exceed 400 ft-lbs, its velocity and bullet weight creates a steep trajectory curve that limits its effective range to self-defence distances.

.45 Auto (.45 Automatic Colt Pistol (ACP)) Handgun Cartridges

**See below for further reference regarding the power rankings listed in the tables above:

MV-Muzzle Velocity
Muzzle velocity when fired from a typical handgun. Measured in feet-per-second.

ME-Muzzle Energy
Muzzle energy when fired from a typical handgun. Measured in foot-pounds.

PF-Power Factor
In shooting competition the Power Factor is used to determine the competitive division in which a particular handgun/cartridge can be used. A simple calculation of the bullet's mass times its muzzle velocity.
PF = bull. mass x muzzle vel.

TKO-Taylor Knock Out Formula
Developed by big-game hunter John Howard Taylor in the 1940's. Calculates the relative effectiveness of bullets for hunting game.
TKO = (bull. mass x muzzle vel. x bull. dia.)/7000

Link back to the main table listing of handgun and rifle cartridges HERE.