Designed by John Moses Browning, the Colt .45 M1911 pistol was an American single-action, semi-automatic pistol. Firing from a closed breech, it was the standard-issue side arm for the United States armed forces from 1911 to 1985. It was widely used in World War I, World War II, the Korean War and the Vietnam War. Its formal designation was M1911 pistol.
Like all pistols, the operation of the Colt M1911 was based on the action of the gases produced when a cartridge was fired. These gases made the slide of the pistol recoil, then ejecting the spent cartridge case as it went back forward, cocking the hammer and reloading the next cartridge in the pistol’s chamber, for firing. Model 1911 used an 8-round magazine to hold the cartridges. Based on M1911 design, today there are pistols which are of higher capacity, usually 12 to 14 rounds. These pistols follow the same basic principles of operation as the standard M-1911.
The pistol was designed to comply with the U.S. Army requirements, that had seen its trusty .38 revolver to be incapable of stopping attackers during its campaign against the Moro guerrillas in Philippines. An Ordnance Board headed by Col. John T. Thompson and Col. Louis A. La Garde had come to the conclusion that the army needed a .45-caliber cartridge, to provide adequate stopping power. But John M. Browning, who was working for Colt, had already designed a semi-automatic pistol, around a cartridge similar to contemporary .38 Super. When the Army announced its interest in a new handgun, Browning re-engineered this handgun to accommodate a .45 diameter cartridge of his own design with a 230 gr. FMJ bullet, and submitted the pistol to the Army for evaluation.
A series of field tests from 1907 to 1911 were held to decide between the Savage and Colt designs. Both designs were improved between each testing over their initial entries, leading up to the final test before adoption. Among the areas of success for the Colt was a 6,000 round test at the end of 1910 attended by its designer, John Browning. The Colt gun passed with flying colors, having no malfunctions, while the Savage designs had 37.