The .45 ACP (Automatic Colt Pistol) is a popular handgun cartridge developed by John Browning in 1905. It was designed for use in the M1911 pistol and has become a standard for many law enforcement and military applications. The cartridge is known for its stopping power and larger bullet diameter, typically measuring .45 inches. The .45 ACP typically fires a 230-grain bullet at a velocity of around 850 feet per second. This combination results in significant energy transfer upon impact, making it effective for self-defense and target shooting. Its popularity has led to a wide variety of firearms chambered for this cartridge, including revolvers and semi-automatic pistols.