The Iconic .45 ACP

.45 ACP Cartridges

The .45 ACP is the most iconic ammunition in the United States. Americans made the ammunition for the U.S. Armed Forces more than 100 years ago and it remains a top choice among firearms enthusiasts, both in the military and in civilian life.

Development of .45 ACP

John Moses Browning designed the .45 Automatic Colt Pistol (ACP) in 1905. Browning wanted to find a replacement for the .38 Long Colt. The U.S. Cavalry needed a more effective bullet than the .44 ball and the .454 bullets since neither had sufficient stopping power. The military ordered that the new ammunition would weigh a minimum of 230 grains, hold a less six rounds, and have a trigger pull more than six pounds.

Browning’s response to the Cavalry was the .45 ACP. The ammo, along with a prototype for an M1911 pistol, was presented to the military. Browning continued to make improvements to the round, and today it has a bullet weight of 230-grains and a muzzle velocity of 830 feet per second (ft/s).

The Colt M1911

In March 1911, the Army had to choose its new standard service weapon. They had field tested many and it came down to a Savage and a Colt. Testers fired each gun 6,000 in various conditions. They reported excellent results – the Savage only had 37 incidents, yet the Colt experienced none, and was therefore chosen as the Colt M1911 was picked to be the official weapon of the U.S. military.

Experts credit the M1911 as one reason the .45 ACP became popular. Many military heroes carried the .45, including Sergeant Alvin York. Tennessee-born Sergeant York was a World War I legend. He is one of the most decorated Army soldiers in history. York received the Medal of Honor for heading an attack on a German munitions nest, killing 25 enemy soldiers and capturing as many as 132. York’s heroics proved to the world that the .45 could stop any target.

In 1985, the U.S. military replaced the coveted .45 ACP with the 9mm. However, members of Delta Force, operators of the Marine Expeditionary Units, and U.S. Special Operations units maintain the option of keeping firearms chambered in .45 ACP.

Civilian Use

Civilians adopted the .45 ACP as their own and its popularity grew rapidly. The round could be adapted to a variety of situations including law enforcement, sports shooting, and self-defense. Users prize the .45 ACP for its mild recoil and accuracy.

Law enforcement agencies throughout the country often use the .45 ACP for its ability to stop assailants. The Federal Bureau of Investigation’s Hostage Rescue Team, the Los Angeles Police Department SWAT and other specialized units opt to carry firearms chambered in .45 ACP.


Users often choose the .45 ACP for self-defense. The round is heavy and creates a deep wound, which can cause significant damage to critical organs and the central nervous system. Shooters also like the .45 ACP because it is affordable and easy to obtain.