Earliest issued version of the .45 ACP (Automatic Colt Pistol) calibre pistol used by the US forces. The original M1911 was also adopted by other nations, the UK (mostly used by the RN, and RFC), Canada, and Norway to name a few.
Designed by John Moses Browning, it utilises a 'swinging link' connection to disengage the bbl from the slide. The Browning GP35 in British service uses a modification of this method using cammed surfaces rather than the swinging link. On request from the American forces the M1911 was slightly modified in 1926 to the M1911A1. Changes included an arched mainspring housing, longer tang, clearance cuts made on the receiver for a more comfortable trigger reach, a longer smooth-faced trigger, a wider foresight and the diameter and rifling of the bbl.
Apart from Colt, this model was also manufactured by many other contractors (Remington Rand, Singer, Ithaca, Union Switch, AMT and Signal, the Springfield Armory), and was also widely copied. Foreign clones include the Norwegian 'Kongsberg Colt' M1914, The Spanish STAR Model P and the Argentinean 'Sistema Colt 1927'. Another Argie clone was the Ballester-Molina .45 which was a slightly cheaper version to produce.
Kongsberg Colten .45
Recognised by the slide catch, The M1914 was also used by the Germans in occupied Norway but never seen action.
STAR Model P
Spanish produced M1911 Clone
Sistema Colt 1927
Argentine produced M1911, It led to the cheaper Ballester-Riguard .45
.455 Webley Variant
In service for over eighty years until replaced as the issue pistol in a contentious and highly politicised decision by the Beretta 92. The 1911 is actually still in US service, albeit in slightly modified form as the 1911 MEU, which is issued to Force Recon Marines.
Comparison of a few specs.
L9A1 Length: 8" - Bbl: 4.72" - Wt: 1.9 lbs - Capacity: 13 rd double staggered magazine - Mv: 1250 fps (nominal) - Calibre: 9mm x 19 - Bullet wt.: 115 gns (FMJ ogive)
(This is a rough guide, there will of course be some differences due to projectile weights, powder types etc.)