Editing M1911 pistol (section)

==Variants==
[[File:Colt M1911 cross-section diagram.jpg|thumb|right|Cross-section diagram, with labeled parts, of original Model 1911 pistol, from official Army description as published in 1917.]]
[[File:COLT M1911A1 fieldstrip noBG 2.jpg|thumb|right|Springfield Mil Spec field stripped]]

Browning's basic M1911 design has seen very little change throughout its production life.<ref name="Manual" />

=== Operation ===
The basic principle of the pistol is recoil operation.<ref name="Manual" /> 

As the expanding combustion gases force the bullet down the barrel, they give reverse momentum to the slide and barrel which are locked together during this portion of the firing cycle. After the bullet has left the barrel, the slide and barrel continue rearward a short distance.<ref name="Manual" />{{page needed|date=March 2021}}

At this point, a link pivots the rear of the barrel down, out of locking recesses in the slide, and the barrel is stopped by making contact with the lower barrel lugs against the frame.   

As the slide continues rearward, a claw extractor pulls the spent casing from the firing chamber and an ejector strikes the rear of the case, pivoting the casing out and away from the pistol through the ejection port.  

The slide stops its rearward motion then, and is propelled forward again by the recoil spring to strip a fresh cartridge from the magazine and feed it into the firing chamber.  

At the forward end of its travel, the slide locks into the barrel and is ready to fire again. 

However, if the fired round was the last in the magazine, the slide will lock in the rearward position, which notifies the shooter to reload by ejecting the empty magazine and inserting a loaded magazine, and facilitates (by being rearwards) reloading the chamber, which is accomplished by either pulling the slide back slightly and releasing, or by pushing down on the slide stop, which releases the slide to move forward under spring pressure, strip a fresh cartridge from the magazine, and feed it into the firing chamber.<ref name="Manual" />

=== Composition ===
Other than grip screws there are no fasteners of any type in the 1911 design. 

The main components of the gun are held in place by the force of the main spring. The pistol can be "field stripped" by partially retracting the slide, removing the slide stop, and removing the barrel bushing. 

Full disassembly (and subsequent reassembly) of the pistol to its component parts can be accomplished using several manually removed components as tools to complete the disassembly.{{citation needed|date=March 2021}}

=== Safety ===
The military mandated a [[grip safety]] and a [[manual safety]].<ref name="Manual" /> A grip safety, [[sear (firearm)|sear]] disconnect, slide stop, half cock position, and manual safety (located on the left rear of the frame) are on all standard M1911A1s.<ref name="Manual" /> 

Several companies have developed a [[safety (firearms)|firing pin block safety]]. Colt's 80 series uses a trigger operated one and several other manufacturers, including Kimber and Smith & Wesson, use a Swartz firing-pin safety, which is operated by the grip safety.<ref>U.S. Patent 2,169,084 (1939)</ref><ref name="Davis">Davis and Raynor(1976), ''Safe Pistols Made Even Safer'', American Rifleman, Jan. 1976</ref> 

Language cautioning against pulling the trigger with the second finger was included in the initial M1911 manual<ref>{{Google books |id=hs9BAAAAIAAJ |page=16 |title=Description of the Automatic Pistol, Caliber .45, Model of 1911, with Rules for Management, Memoranda of Trajectory, and Description of Ammunition}} (published in 1917)</ref> and later manuals up to the 1940s.

=== Calibres ===
In addition to the .45 ACP (Automatic Colt Pistol), M1911 models chambered for [[.455 Webley|.455 Webley Auto]], [[.38 Super]], [[9×19mm Parabellum]], [[7.65mm Parabellum]], [[9mm Steyr]],<ref>{{cite web |author=Wiley Clapp |title=The 1911: Not Just a .45 |url=http://www.americanrifleman.org/articles/the-1911-not-just-a-45/ |url-status=live |archive-url=https://web.archive.org/web/20130811021831/http://www.americanrifleman.org/articles/the-1911-not-just-a-45 |archive-date=2013-08-11 |access-date=2013-08-25 |work=American Rifleman}}</ref> [[.400 Corbon]], and other cartridges were offered. 

The M1911 was developed from earlier [[Colt's Manufacturing Company|Colt]] semi-automatic designs, firing rounds such as [[.38 ACP]]. 

=== Interwar changes ===
Battlefield experience in World War I led to some more small external changes to the M1911, completed in 1924. 

The new version received a modified type classification, M1911A1, in 1926 with a stipulation that M1911A1s should have serial numbers higher than 700,000 with lower serial numbers designated M1911.<ref>Canfield, Bruce N. ''[[American Rifleman]]'' June 2005, p. 26</ref> 

The M1911A1 changes to the original design consisted of a shorter trigger, cutouts in the frame behind the trigger, an arched mainspring housing, a longer grip safety spur (to prevent [[hammer bite]]), a wider front sight, a shortened hammer spur, and simplified grip checkering (eliminating the "Double Diamond" reliefs).<ref name="Poyer" /> 

These changes were subtle and largely intended to make the pistol easier to shoot for those with smaller hands. No significant internal changes were made, and parts remained interchangeable between the M1911 and the M1911A1.<ref name="Poyer" />