The Colt Single Action Army, also known as the "Peacemaker", is a single action revolver. It was designed for the U.S. cavalry by Colt and adopted in 1873, and it was perhaps the most prolific handgun in the Wild West.
The Single Action Army uses .45 Colt cartridges (often known as '.45 Long Colt' or '.45 LC'), which should not be confused with the .45 Automatic Colt Pistol (.45 ACP) cartridge commonly used in semi-automatic pistols. Standard .45 ACP ammunition is regulated to under 21,000 lbf/in² (145 MPa), while .45 Colt must be kept under 14,000 lbf/in² (97 MPa) to be safe in older guns. Despite the lower pressure, the muzzle velocity of the Single Action Army is about the same as—or slightly higher than—many .45 ACP pistols, due to its long barrel length. Using the original load intended for the Single Action Army, a 250 grain (16 g) cast lead bullet over 40 grains (2.6 g) of FFg black powder, muzzle velocities of around 1000 ft/s (300 m/s) can be achieved. However, because that load pushed the chamber pressure limit of the original 1873 revolvers the government cut the powder charge down to 36 grains (2.3 g) of FFg black powder, which gave the bullet the 800 to 900 ft/s (240 to 270 m/s) muzzle velocity.
The .45 LC was the initial cartridge the SAA was chambered for in 1873. The US Army approved a second standard military handgun of the same period, a Smith and Wesson "breaktop" single action with modifications by a US Army Major by the name of Schofield. That gun took a shorter, slightly less potent version of the .45 LC, called the .45 Schofield, which would also fit in the Colt SAA. The Colt quickly gained favor over the S&W and remained the primary US military sidearm until 1892. Which was replaced by the Colt M1892, then the US Army temporary used the Peacemaker for a short time.
By 1876 the Colt SAA was being offered in additional calibers for civilian and foreign military sales. Many were sold in .44-40 Winchester to allow cross-compatibility with the Winchester '73 lever action rifle. Additional calibers for the SAA included .38-40 (with ballistics similar to modern police .40 S&W semi-auto ammo), .32-20, .44 Russian and .44 Special. The SAA is now sold in more modern calibers as well, including the .357 Magnum.
The term Single action refers to the behavior of the trigger. Its hammer must be cocked manually before each shot, and the trigger performs only a single action, releasing the hammer. Most modern revolvers are "double action," as pulling the trigger will both cock and release the hammer.
Like many other contemporary revolvers, the cylinder of the Single Action Army can hold 6 rounds. However, because there is no mechanism which prevents a round from discharging a loaded chamber if the hammer is struck forcibly, five rounds are usually loaded. Although many modern reproductions, such as those made by Beretta, utilize a transfer-bar safety which prevents such an accidental discharge, many people still choose to load only 5 cartridges for the sake of historical accuracy. In the popular sport of cowboy action shooting, even if one has a modern revolver, like the Ruger Vaquero, with the transfer bar safety (in which it is perfectly safe to load and carry six in the cylinder), they are only allowed to load five and keep the hammer on an empty chamber.
The common loading method is to load 1, miss 1, then load the rest. This causes the empty chamber to be under the hammer. When the hammer is cocked, it will rotate the chamber to one with a round inside. Furthermore, as the swing-out cylinder had yet to be invented, Colt Peacemakers are loaded by opening a loading gate on the right side of the gun, behind the cylinder. Each round is loaded individually as the user turns the cylinder and ejects the casing with the built-in ejection rod attached below the barrel. Colt's cartridge powerful, and because the Colt revolver tended to be a more sturdy gun because of its solid frame, the Colt was the final choice for the U.S. Army and, therefore, for any peace officer or civilian who could afford one.
The loading gate for rounds was on the right side as a nod to use on horseback. The user was supposed to hold both the reins and gun in the left hand and insert rounds with the right.
The Single Action Army is still being manufactured today, although antique Peacemakers are obviously rare and highly regarded as collectors items. The gun is perhaps most widely associated with the wild west and spaghetti westerns, although many films and cultural shows still use this.
All original, good condition first generation Single Action Armys, those produced between 1873 and 1941, are among the most valuable to the collector. Especially valuable, often going for well over $10,000, are the OWA and the Nettleton 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 Little Bighorn, oddly Custer himself never carried a peacemaker on the day of the battle, instead he carried a pair of English built Bull dog revolvers.
Henry Nettleton was the ordinance 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.
Another historical military SAA revolver is the Artillery Model. It was issued to the rear-echelon troops, artillerymen, and such during the Spanish-American war period. Following the Indian wars, in 1895, the cavalry SAAs had fallen into disrepair and had been sent back to the Colt factory or Springfield Armory to be refurbished, fit with a shorter barrel, (from a 7 1/2 in (191mm) to a 5 1/2 in (140mm) barrel) and re-issued. The standard military revolver at the time was the Colt double action New Army revolver chambered in 38 Colt. Theodore Roosevelt's Rough Riders charged up San Juan hill wielding the Artillery Model. Artillery models can usually be identified by the original inspector's cartouche (such as the OWA or HN) on the left side of the grips and the cartouche of Rinaldo A. Carr (RAC), the inspector who inspected the refurbished guns, on the right side.
The Single Action Army has been copied by numerous makers both in America and in Europe. The two major makers of Colt replicas are Aldo Uberti in Italy, which is a property of Beretta, and United States Firearms Mfg. Co. in Hartford Connecticut. Both companies make superb replicas that are much more affordable than the real Colt.
A number of "near clones" of the Colt SAA have appeared which mimic the size and feel of the SAA while offering a modern transfer bar ignition system similar to modern Double Action (DA) revolvers. Unlike the SAA and "true clones", these can be carried with all six rounds loaded versus "five up carry and hammer on the empty cylinder". After Beretta bought Uberti they ordered a high-end SAA near-clone with a transfer bar known as the Beretta Stampede. The other two transfer bar SAA near-clones are the Ruger "New Vaquero" and the Taurus Gaucho. These three are much safer for the newbie "cowboy shooter" while being close enough to SAA ergonomics to fit in the same holsters. The Ruger "Original Vaquero" looks a lot like the SAA but is built on a bigger frame able to take the .44 Magnum and is not considered an "SAA clone" like the "New Vaquero".
General Patton carried an ivory handled Colt peacemaker which he used in the Mexican Punitive Expedition of 1916 as well as carrying one during the second world war.
Famed British adventurer and soldier T.E. Lawrence ("of Arabia") had a special fondness for this weapon, because it saved his life during one of his pre-World War I trips to Mesopotamia; he was jumped by an Arab bandit who stole the gun and tried to kill Lawrence, but Lawrence's assailant couldn't because he did not understand the revolver mechanism. Lawrence thereafter always carried one of these weapons for good luck..
- See Lowell Thomas, With Lawrence In Arabia (1924)