Colt Single Action Army The Colt Single Action Army — also known as the Single Action Army , SAA , Model P , Peacemaker , M1873 , and Colt . 45 — is a single action revolver with a revolving cylinder holding six metallic cartridges . It was designed for the U . S . government service revolver trials of 1872 by Colt ' s Patent Firearms Manufacturing Company , today Colt ' s Manufacturing Company , and was adopted as the standard military service revolver until 1892 . The Colt Single Action Army has been offered in over 30 different calibers and various barrel lengths . Its overall appearance has remained consistent since 1873 . Colt has discontinued its production twice , but brought it back due to popular demand . The revolver was popular with ranchers , lawmen , and outlaws alike , but current models are mostly bought by collectors and reenactors . Its design has influenced the production of numerous other models from other companies . The Colt . 45 Single Action Army revolver is a famous piece of Americana , known as " The Gun That Won the West " . History . Bound by the Rollin White patent ( ) and not wanting to pay a royalty fee to Smith & Wesson , Colt could not begin development of bored - through revolver cylinders for metallic cartridge use until April 4 , 1869 . For the design , Colt turned to two of its best engineers : William Mason and Charles Brinckerhoff Richards who had developed a number of revolvers and black powder conversions for the company . Their effort was designed for the United States government service revolver trials of 1872 by Colt ' s Patent Firearms Manufacturing Company and adopted as the standard military service revolver . Its original moniker was the " New Model Army Metallic Cartridge Revolving Pistol " . The very first production Single Action Army , serial number 1 , thought lost for many years after its production , was found in a barn in Nashua , New Hampshire in the early 1900s . It was chambered in . 45 Colt , a centerfire design containing charges of up to of fine - grained black powder and a blunt roundnosed bullet . Relative to period cartridges and most later handgun rounds , it was quite powerful in its full loading . The Colt Single Action Army revolver , along with the 1870 and 1875 Smith and Wesson Model 3 " Schofield " revolver , replaced the Colt 1860 Army Percussion revolver . The Colt quickly gained favor over the S & W and remained the primary US military sidearm until 1892 when it was replaced by the . 38 Long Colt caliber Colt Model 1892 , a double action revolver with swing - out cylinder . By the end of 1874 , serial no . 16 , 000 was reached ; 12 , 500 Colt Single Action Army revolvers chambered for the . 45 Colt cartridge had entered service and the remaining revolvers were sold in the civilian market . The Colt . 45 is a famous piece of American history , known as " The Gun That Won the West " . First generation 1873 – 1941 . The Single Action Army became available in standard barrel lengths of 4¾ " , 5½ " as well as the Cavalry standard , original 7½ " . The shorter barrelled revolvers are sometimes called the " Civilian " or " Gunfighter " model ( 4¾ " ) and the Artillery Model ( 5½ " ) . There was also a variant with a sub 4 " barrel , without an ejector rod unofficially referred to as the " Sheriff ' s Model " , " Banker ' s Special " , or " Storekeeper " . From 1875 until 1880 Colt marketed a single action revolver in . 44 rimfire Henry caliber in a separate number range from no . 1 to 1 , 863 . A " Flattop Target Model " was listed in Colt ' s catalogs from 1890 to 1898 . Colt manufactured 914 of these revolvers with a frame which was flat on top and fitted with an adjustable leaf rear sight . The front sight consisted of a base with an interchangeable blade . In 1896 , at serial number 164 , 100 , a spring - loaded base pin latch replaced the cylinder pin retaining screw and by 1900 , at serial number 192 , 000 , the Colt Single Action was certified for use with smokeless powder . In 1920 , larger , highly visible sights replaced the original thin blade and notch . The revolvers remained essentially unchanged from that point until cessation of manufacture at the beginning of World War II . From 1873 through 1940 ( with small numbers assembled during and after World War II , the so - called " Pre - War , Post - War " model ) , production of the Colt Single Action Army reached 357 , 859 . This is identified as the " Pre War " or " First Generation " of the model . Calibers , at least thirty in all , ranged from . 22 rimfire through . 476 Eley , with approximately half , or 158 , 884 ( including Bisley and Flat Top Target variations ) , chambered for . 45 Colt . The next most prevalent were the . 44 - 40 Winchester Center fire ( WCF ) at 71 , 392 ; 38 - 40 ( 38 WCF ) at 50 , 520 ; 32 - 20 Winchester ( 32 WCF ) at 43 , 284 and , the 41 Colt at 19 , 676 . Military use . All original , good condition , U . S . Cavalry and Artillery Single Action Armies ( those produced between 1873 and 1891 ) are among the most valuable to the collector . Especially valuable , often going for well over $ 10 , 000 , are the OWA ( Orville Wood Ainsworth ) and the rare Henry Nettleton inspected Single Action Army Colts . The OWA Colt refers to the earliest issued Single Action Army guns which were inspected by Orville W . Ainsworth . Ainsworth was the ordnance sub - inspector at the Colt factory for the first 13 months ( Oct . 1873 to Nov . 1874 ) of the Single Action Army ' s production . It was Ainsworth who inspected the Colts used by Col . G . A . Custer ' s 7th Cavalry at the Battle of the Little Bighorn . The number range of possible Little Bighorn Colts is 4500 - 7527 . Henry Nettleton was the U . S . Principal Sub - inspector in 1878 at the Springfield Armory . Second only to the OWA Colts , Nettleton Colts are prized by serious collectors . Both the Nettleton and OWA Colts have the cartouche ( OWA or HN ) on the left side of the wood grip . By the mid - 1870s , the Army had purchased a significant number of Smith and Wesson Schofield revolvers chambering a shorter . 45 round . Logistical problems arose because the ammunition was not interchangeable . The Colt revolvers would accept the shorter round but not vice versa . For a time , the Government stopped orders for the longer Colt cartridge and used the Smith and Wesson round exclusively . The S & W Schofield was soon retired and sold to the civil market . The largest group of U . S . Colt Cavalry revolvers was inspected by David F . Clark , his D . F . C . cartouche being encountered on revolvers inspected from 1880 to 1887 . During 1893 , the . 45 U . S . Colt Single Action Army revolver was retired by the Cavalry and replaced by the . 38 caliber Colt Model 1892 Double Action Army revolver . The . 45 Single Action Army revolver was still standard issue to the Infantry , Artillery and other branches of the U . S . Army . In 1895 - 96 , the Government returned 2000 SAA revolvers to Colt ’ s to be refurbished ; 800 were issued to the New York Militia with the 7 ½ ” barrel and 1200 were altered to a barrel length of 5½ " . In 1898 , 14 900 of the SAA revolvers were altered the same way by Springfield Armory . The original records of the War Department do refer to these revolvers with the shortened barrel as the “ Altered Revolver ” . The name “ Artillery ” is actually a misnomer , maybe because the Light Artillery happened to have the first units armed with the altered revolver . The Artillery Single Actions were issued to the Infantry , the Light Artillery , the Volunteer Cavalry and other troops because the standard issue . 38 caliber Colt M 1892 double action revolver was lacking in stopping power . For that reason , the . 45 Artillery SAA Revolvers were used successfully by front troops in the Spanish - American War and the Philippine - American War . Theodore Roosevelt ' s Rough Riders charged up San Juan Hill wielding the . 45 caliber Artillery Model . The Artillery Model usually had mixed numbers . It can be identified by the U . S . on the frame , the inspector ' s stamps on different parts ( such as a tiny A for Orville W . Ainsworth , DFC , HN , RAC for later inspectors and K for replacement parts ) and the cartouche of Rinaldo A . Carr ( RAC ) , the inspector who inspected the refurbished guns , on the grip . The Colt Frontier Six - Shooter . The Colt Frontier or Frontier Six - Shooter was a Colt ' s 1873 " Model P " type revolver , manufactured in . 44 - 40 Winchester caliber instead of . 45 Colt ( in which configuration it was called the Single Action Army ) , so as to be compatible with Winchester Model 73 ammunition . Production began in 1877 . " Colt Frontier Six - Shooter " was the actual name of the Colt pistol model , and this was acid - etched on the left side of the barrel . After 1889 , the legend was roll - stamped until 1919 , when the caliber designation " . 44 - 40 " was added . Later Colt 1878 Double Action Army Models also wore this designation on the barrel when chambered in 44 WCF / 44 - 40 Winchester . The Bisley 1895 Model was the final Colt to wear the Frontier Six Shooter designation . Users of the . 44 - 40 Winchester cartridge in the Far West appreciated the convenience of being able to carry a single caliber of ammunition which they could fire in both revolver and rifle . The " Colt Frontier Six Shooter " Revolver and the Winchester Model 1873 or the Winchester Model 1892 in . 44 - 40 WCF caliber were one of the most common combinations seen in " the Old West " . The Bisley Model ( 1894 - 1915 ) . The Colt Bisley was introduced in 1894 as a target pistol . The name Bisley came from the famous firing range in Bisley , England . The Colt Bisley can be distinguished by the longer grip , the wider hammer spur , and the wider trigger . The distinguishing feature of the Bisley Target Model is the topstrap , which is flat and fitted with a sliding rear sight , adjustable for windage only . The front sight is a removable blade , which fits into the slotted base attached to the barrel . The revolvers were supplied with different blades for elevation . The Bisley mainspring is longer than the SAA mainspring , and the two are not interchangeable ; it is attached to the hammer with a stirrup via a forked upper end . The serial numbers are stamped on the frame , the backstrap and the trigger - guard at the end of production , with tiny dies . Bisleys were serial - numbered in the range of 156300 – 331916 , in the same sequence as the Single Action Army . All Bisleys after No . 161 , 376 had " BISLEY MODEL " with the caliber stamped on the left side of the barrel , which is rare for older Colt revolvers . The most common calibers were . 32 - 20 , . 38 - 40 , . 45 Colt , . 44 - 40 , . 41 Colt , and the British calibers . 450 Eley and . 455 Eley . A total number of 44 , 350 were manufactured . Production of the Bisley was terminated in 1912 , but serial No . 331916 was shipped after the First World War . Most Bisley Standard Model Revolvers which were shipped to a United States address were not used for target shooting but for self - defense because the grip and hammer were ideal for fast shooting . Buntline Special . Wyatt Earp biographer Stuart N . Lake popularized the myth of the Buntline Special . In his highly fictionalized biography , " Wyatt Earp : Frontier Marshal " , published in 1931 , he wrote that Earp and four other lawmen — ' Bat ' Masterson , Bill Tilghman , Charlie Bassett and Neal Brown — were presented with a customized revolver with a - long barrel . However , on October 26 , 1881 , the day of the Fight at the O . K . Corral , Wyatt Earp carried an 1869 . 44 caliber Smith & Wesson American Model , with an 8 inch barrel . Second - generation ( 1956 - 1974 ) . At the beginning of World War II , Colt ceased production of the Single Action Army revolver to devote more time to filling orders for the war . When the war ended , no plans were made to revive the Single Action Army revolver as the design was seen as obsolete . However the advent of television and Western themed movies created customer demand for the revolver , so Colt resumed manufacture in 1956 with the Second Generation line of Single Action Army revolvers . These Second Generation Colt Single Action Army revolvers were produced from 1956 – 1974 and carried serial numbers in the range of 0001SA to 73 , 205SA . Due to the popularity of the television show , " The Life and Legend of Wyatt Earp " , Colt introduced the aforementioned Buntline Special as a Second generation offering from 1957 - 1974 . From 1961 to 1975 , Colt offered an adjustable - sight model known as " The New Frontier " , capitalizing on President John F . Kennedy ' s campaign slogan . Colt manufactured 4200 of these revolvers , including 70 built on the Buntline frame . Third - generation ( 1976 to present ) . The Third Generation began in 1976 , characterized by a change in barrel thread pitch and a solid cylinder bushing replacing the removable / replaceable part from the first and second generations . This series ran until 1982 as a limited - issue product with the serial number range of SA80 , 000 to SA99 , 999 . In 1994 , production resumed with the increase in popularity of " Cowboy Action Shooting " matches . These models are known either as " Late Third Generation " or sometimes Fourth Generation . with the serial number convention changing yet again , starting with S02001A and continuing with the " S " prefix and " A " suffix to 2009 . Colt currently offers the Single Action Army in one of two finishes : either an all - nickel , or blued with color case - hardened frame ; in the traditional three barrel lengths : 4¾ " , 5½ " and 7½ " ; and six chamberings : 32 - 20 , 38 - 40 , 44 - 40 , . 38 Special , 357 Magnum or 45 Colt ; a total of 36 variations . Colt manufactured Third Generation Buntlines and New Frontiers through the Colt Custom Shop , as well as many engraved pistols . In 2010 , Colt released a " revival " of the Frontier Six Shooter with a nickel finish . The Colt Cowboy . Starting in 1999 , Colt began manufacturing a version of the Single Action Army revolver with a modern transfer bar safety , allowing it to be carried with the hammer resting on a loaded chamber . The Colt Cowboy , as it was named , was designed to be more affordable than the Single Action Army . It was offered with barrel lengths of 4 . 75 inches , 5 . 5 inches , and 7 . 5 inches . The 7 . 5 inch variant was discontinued in 1999 , as was the 4 . 75 inch variant which was reintroduced in 2002 . Manufacturing of the Colt Cowboy was discontinued in 2003 . Engraving . Colt engraved less than one percent of its first generation production of the Single Action Army revolver , which makes these engraved models extremely rare and valuable with collectors . Engraved pieces were often ordered by or for famous people of the day , including lawmen , heads of state , and captains of industry . This tradition began with the founder , Samuel Colt , who regularly gave such examples away as a means of publicity for Colt . Colt employed a number of highly skilled engravers , many of whom were highly trained artisans who emigrated from Europe . These artisans were known for inlaying gold , silver , and precious stones in their work . Many of these engraved pieces were adorned with stocks made of ivory or pearl with engraving and inlays as well . About 400 of the Second Generation Colt Single Actions were factory engraved by Colt . The factory engravers of the period were Alvin Herbert , Earl Bieu , Dennis Kies , Robert Burt and Leonard Francolini . One of the most sought - after engravers who have worked on Colt revolvers was Alvin White and the shop of A . A . White Engravers . Operation . The Single Action Army action is a refinement of the earlier Colt percussion revolvers and the Colt 1871 cartridge revolver . The cylinder is mounted on a central axis and operated by a hand with a double finger whose more extended action allowed the cylinder - ratchet to be cut in a larger circle , giving more torsional force to the cylinder . Three notches on the face of the hammer engage the sear portion of the trigger , affording four basic hammer positions . The hammer when fully lowered rests within the frame . Drawn slightly to the rear , the hammer engages the safety notch of the sear and holds the firing pin out of direct contact with a chambered cartridge . Like the earlier percussion revolvers , the Single Action Army was designed to allow loading of all of the chambers . The safety notch replaced pins on the rear of the percussion revolver cylinders which served the same purpose as the safety position by preventing hammer contact with the primer / percussion cap . However , many users adopted the practice of leaving one empty chamber under the hammer because a sharp blow could damage the mechanism and allow the fully loaded revolver to fire . This practice is now universally recommended . Drawn back about half way , the hammer engages the second notch . This cams the cylinder bolt out of engagement and allows the cylinder to rotate for loading . Fully cocked , the revolver is ready to fire . Cartridge ejection is via the spring - loaded rod housed in a tube on the right side of the barrel . The loading sequence is as follows : It is possible to fire the SAA rapidly by holding down the trigger and " fanning " the hammer with the other hand . Ed McGivern dispelled the myth of the inaccuracy of this procedure by shooting tight groups while fanning the revolver . Calibers . By 1878 the Colt SAA was being offered from the factory in additional calibers for civilian and foreign military sales . Many were sold in . 44 - 40 Winchester Center Fire ( WCF ) , introduced in 1878 to allow cross - compatibility with the Winchester ' 73 lever action rifle ; this model was called the " Colt Frontier Six - Shooter " which was etched and later roll - stamped on the left side of the barrel . Additional period calibers for the SAA included . 38 - 40 Winchester ( 38 WCF ) introduced in 1884 , the . 32 - 20 Winchester ( 32 WCF ) introduced in 1884 , the . 41 Colt introduced in 1885 , the . 38 Long Colt in 1887 , the . 38 Special and the . 357 Magnum in the 20th Century . Some of the separately - serialized . 44 Henry rimfire revolvers were rechambered to . 22 rimfire after 1885 . The SAA at one time or another was offered in dozens of calibers from . 22 rimfire to . 476 Eley , though the . 45 Colt has always been the most common . A scaled - down . 22 rimfire version called the Scout or Frontier Scout was available in the late 20th Century . 45 Colt cartridge variations . The first Colt Single Action Army prototypes were manufactured in . 44 American caliber for the 1872 government trials , as the . 44 American was the cartridge used in the 1000 Smith & Wesson Model 3 revolvers issued to the troops . After the tests , the Colt was declared the superior revolver and the government specified that a . 45 caliber cartridge would be required . With the adoption of the Colt Single Action Army revolver in 1873 , the service cartridges were Copper - cased . 45 centerfire Benét inside primed “ Colt ’ s Revolver Cartridges ” loaded with 30 grains of black powder and an inside lubricated bullet of 250 grain . They were manufactured at Frankford Arsenal , Philadelphia , PA , through 1874 . In 1875 , the cartridge was shortened so that it would also function in the newly adopted S & W Schofield revolver . It was designated “ Revolver Cartridge ” and loaded with 28 grains of black powder and a bullet of 230 grain . The Bénet - primed cartridges were manufactured until 1882 and then replaced by reloadable cartridges with brass cases and external primers . The original . 45 Colt black - powder load of 40 grains propelled the 250 - 255 grain bullet at a nominal . Authors John Taffin and Mike Venturino have demonstrated that modern black - powder loadings of the 45 Colt cartridge frequently achieve velocities in the vicinity of with the 7½ " " cavalry " barrel length , even though modern solid - head cases make it impossible to load a full 40 grains . Specifications for 20th - century smokeless loads set velocity with a round - nosed flat - point bullet at providing energy . The current version of the 45 Colt differs from the original cartridge case in that the rim is significantly larger ( with a groove immediately above it ) and the internal aspect of the primer pocket is surrounded by solid brass instead of protruding into the powder chamber . This " solid head " case is stronger and resists deformation of the primer pocket . Some commercial and custom revolvers and single - shot pistols ( such as the Ruger Blackhawk , T / C Contender and others ) employ high - pressure loads that are dangerous in the Single Action Army and other vintage arms chambered for the 45 Colt cartridge , especially 19th - century " pre - smokeless " revolvers which should be fired ( if at all ) only with black powder or light smokeless loads . Prior to World War II , the 45 Colt used a groove diameter of . 454 " ; post - WW II production adopted the . 452 " groove diameter of the 45 ACP . Legacy . The power , accuracy and handling qualities of the Single Action Army ( SAA ) made it a popular sidearm from its inception , well into the 20th century . The association with the history of the American West remains to the present century , and these revolvers remain popular with shooters and collectors . George S . Patton , who began his career in the horse - cavalry , carried a custom - made SAA with ivory grips engraved with his initials and an eagle , which became his trademark . He used it during the Mexican Punitive Expedition of 1916 to kill two of Pancho Villa ' s lieutenants , and carried it until his death in 1945 shortly after the end of World War II . In the early and mid - 20th century , original Peacemakers lacking historical provenance and not in pristine condition were not particularly valuable . They served as raw material for early enthusiasts such as Elmer Keith , Harold Croft and R . F . Sedgley who modified the revolvers to enhance performance and experimented with more effective ammunition . At the beginning of the 21st Century , first and second generation SAA ' s are highly regarded as collectors ' items and often considered too valuable to shoot . After World War II , new interest in the SAA started and firearms enthusiast William R . Wilson recognized the need and the opportunity . In 1953 Wilson founded the Great Western Arms Company to produce an almost - exact clone of the old Colt SAA for television and movie westerns . The Great Western revolvers were manufactured in Los Angeles . Later Colt editions are more common , and various copies and near - copies of the revolver are made by Uberti of Italy . Uberti is now owned by Beretta , which itself produces the Beretta Stampede . American manufacturers include Colt Manufacturing Company , which still retains the model in its catalog . U . S . Fire Arms Mfg . Co . builds several variations that are true to the original first and second generation specifications . STI International has introduced a very precisely made Single Action Army with a modified hand / spring assembly designed to last longer than the originals . The Single Action Army is the precursor and inspiration for modern sporting revolvers from John Linebaugh , Freedom Arms , Ruger , Cimarron , and others . In 2010 , knowing the significance of the Peacemaker in the Copperstate ' s Wild West history , Arizona State Rifle and Pistol Association President Noble C . Hathaway and Cast Bullet Director Dan Walliser put forth a survey to the state of Arizona . The survey was to determine what popular " Old West " firearm should represent the state of Arizona as the official State Firearm . The Colt Patent Firearms Single Action Army won by a 38 % margin . Soon after , Hathaway submitted a bill to the Arizona legislature to make the Peacemaker the official state firearm . On the last day of the 2010 - 2011 regular legislative session , Arizona Senate Bill 1610 was passed , and within days Governor Jan Brewer signed the bill into law . Arizona is only the second state to have an official firearm behind Utah ' s recent adoption of the Colt M1911 pistol , in honor of the pistol ' s designer , John Browning , who was also a Utah native .