M1911 is a single action, semi-automatic, magazine-fed, recoil operated pistol chambered for the .45 ACP cartridge. There are 7 rounds in a standard clip. It is more effective than 9mm and 40sw. It was used as standard-issue service pistol of the U.S. Armed forces from 1911. The pistol remains in service with various law enforcement agencies across the U.S, such as the FBI, along with some US Special Operations soldiers. M1911 are still used today worldwide.
M1911 on Wikipedia