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The M1911 (often referred to simply as 1911) is a single action short recoil-operated semi-automatic pistol, chambered in .45 ACP. It features a 7 round magazine and has an effective range of approximately 50 meters. Its name sake derives from the year it was first produced, in 1911.

The M1911 produced by Colt was the standard sidearm of the U.S. military from 1911 to 1985, marking one of the longest periods of a standard weapon, of nearly 74 years. The M1911 was used by U.S. soldiers in World War I, World War II, Korean War, and Vietnam War.


The history of the Colt M1911 began in early 1900s, when famous designer John M. Browning began to develop semi-automatic pistols for Colt's Patent Firearms Manufacturing Company. In 1905, Browning designed two .45 cal. semi-automatic pistols in response to government interest in a higher-caliber sidearm to replace the standard-issue .38 cal. revolvers then in use (primarily the Colt M1892). The two designs were hammer and hammerless versions of the same basic design and show a clear resemblance to the


Colt 1911 featured on Top Shot

M1911. In 1906-1907 the U.S. military tested several semi-automatic pistols including designs from Colt, Luger, Savage, and others. These weapons were deemed unsatisfactory for military use and the competitors were asked to improve their designs in anticipation of new trials in 1910. The Colt Model 1905 remained a popular civilian pistol. However, Browning and Colt spent the next three years engineering improvements to the Model 1905. In 1911, after further extensive testing, the new pistol and its cartridge were adopted for U.S. military service as the M1911. Prior to and during World War I, more than one million of these guns were manufactured by Colt, Springfield Armory, Remington UMC, Burroughs, Savage, and others. The rights to manufacture Colt/Browning design were also sold to some foreign countries, such as Norway and Argentina.

In 1926, the original design was modified for ergonomics, mass production, and parts interchangeability, following US Army Ordnance Department recommendations. These changes included:

  • 1. Wider front blade sight
  • 2. Shorter hammer spur
  • 3. Shorter trigger
  • 4. Curved mainspring housing
  • 5. Simplified grip panel checkering
  • 6. Index finger reliefs behind the trigger
  • 7. Longer grip-safety spur
  • 8. New barrels rode the link into battery instead of utilizing the lower lugs.

The improved design was adopted by the US Military as the M1911A1 pistol. Almost 2.7 million M1911 and M1911A1s were produced for military use during World War I, World War II, Korea, and Vietnam. The M1911 continued to serve with distinction until 1985 when it was officially replaced with the Beretta M9 pistol (US-made Beretta 92FS). The M1911 is still popular among some U.S. special operations units due to its precison and the belief that .45 ACP FMJ is more effective than 9mm NATO FMJ. More units are starting to move away from the M1911, however, as it is rather maintenance-intensive.

Commercial versions of the M1911 are known as Government models. In 1929, Colt introduced a Government model in its new chambering, the .38 Super Automatic, a high power version of the earlier .38 Automatic cartridge. The .38 Super has a higher muzzle velocity which produces a flatter trajectory to the target and therefore greater longer-range accuracy. The smaller cartridge allowed a larger magazine capacity (9 rounds) and sold well on the police market. The .38 Super version is still manufactured and used mostly as a competition gun due to its extreme accuracy.

From 1970 to 1983, Colt manufactured the Mk. IV Series 70 Government model pistol which closely resembled the M1911A1, but utilized a collet-style barrel bushing. This bushing, while precise, tended to be fragile and was often replaced with fitted standard bushings. Since 1983, Colt has manufactured the Mk. IV Series 80 Government model, which features an internal firing pin safety. The latest Colt product, the M1991A1, also featured Series 80 slide with firing pin safety.

Colt also developed compact versions of its full-size commercial guns. The so called "Commander" versions (available as Combat Commanders, Lightweight Commanders with alloy frames, etc.) have shortened barrels and slides (barrel length 108mm, or 4.25 inch), with the standard size frame and grip, and standard magazine capacity of 7 rounds in .45 ACP. These guns were also available in .38 Super and 9mm Luger chamberings. In 1972, US Army adopted the M15 General Officers Model Pistol, developed by the Rock Island Arsenal, as a self-defense weapon for high level army officers. The M15 has a brass plate insert in the left grip panel, where the name of the owner should be engraved.

An even more compact version, the Colt Defender, has a shorter grip that limits magazine capacity to 6 rounds of .45 ACP. The Defender has a barrel length of 76mm length (3 inch). Commercial Colt Officers' pistols are similar to Defenders.

There are numerous M1911 "clones" manufactured by companies worldwide, including Springfield Armory, Les Baer, Kimber, Wilson, STI, Para-Ordnance, and many others. Many M1911-patterned pistols are custom built for service duty, sport shooting, and self defense.

Design Details

The M1911 is a short-recoil operated, locked breech, semi-automatic pistol. It has a single action trigger with a frame-mounted manual safety that locks the sear to the hammer as well as preventing slide movement when engaged. The manual thumb safety may be engaged only when the hammer is fully back. An additional "grip" safety is incorporated into the rear of the grip that locks the trigger when the gun is not held in the hand properly.

The barrel and slide are interlocked via lugs on the upper part of the barrel, just ahead of the chamber. After firing, the barrel and slide recoil for a short distance, before the rear part of the barrel is lowered by a tilting link that separates the barrel from the slide. The slide continues back, extracting and ejecting the spent case, compressing a recoil spring located under the barrel, and cocking the hammer. The recoil spring then returns the slide and barrel to battery, chambering a new round on the way back. When the magazine is empty, the magazine follower activates the slide stop, locking the slide in the open (rear) position. The gun is fed from a single stack, seven-round magazine. The magazine release button is located on the left side of the frame, just behind the trigger guard.

Eight-round magazines are also available for the M1911, and some variants offer "double-stack" magazines that hold 14 rounds.

Recoil operation is based on the law of conservation of momentum (Newton's Third Law, commonly paraphrased as "every action has an equal but opposite reaction"). In a recoil-operated firearm such as the M1911, the momentum of the projectile traveling forward out of the barrel is balanced by an equivalent recoil force acting on the barrel/slide assembly in the rearward direction. A recoil-operated self-loading firearm depends on proper "tuning" of the projectile's momentum (its mass multiplied by its velocity) so that there is sufficient recoil force generated to perform the extraction, ejection, and chambering of the next round. Optimal operation of a standard M1911 occurs with the use of .45 ACP ammunition weighing 230 grains traveling at approximately 250 meters/second.


Modern Gov't/1911 variants may differ, more or less, from this description: some guns may have widebody frames that can accept dual stack, high capacity magazines; frames could be made from steel, aluminum alloys or polymer; some could have Double Action or even Double Action Only triggers, ambidextrous safety switches and slide stops, and other modifications.

There are compact variants of the M1911, and variants of the M1911 that are different calibers; 9x19mm Parabellum variants are fairly common. The Colt Delta Elite is a M1911 modified to accept the 10mm Auto cartridge.


See also