The Colt Single Action Army (SAA), also known as the Model P, Peacemaker, or M1873, is a single-action revolver that was developed by Colt for the U.S. Army trials in 1872. It was adopted as the Army's standard-issue sidearm from 1873 to 1892. Over the years, more than 30 different calibers and various barrel lengths have been produced for the Colt SAA, but its basic design has remained largely unchanged since its inception. The revolver was so popular that Colt reinstated production twice after initially ceasing it, leading to three distinct generations: the first (1873–1941), second (1956–1974), and third (1976–present). The SAA earned the nickname "Peacemaker" due to its widespread use by ranchers, law enforcement, and outlaws, becoming a symbol of the American West. While originally designed for the military, it became a favorite among various groups, contributing to its legendary status. The original U.S. Cavalry model featured a 7.5" barrel and a total length of 13". Over time, other barrel lengths like the 4.75" and 5.25" became popular, with shorter versions like the Sheriff's model having 3 or 4" barrels. The SAA's action was a significant improvement over earlier Colt revolvers, featuring a rotating cylinder mounted on a central axis. This design increased the cylinder’s torsion force, improving reliability. The revolver's hammer has four distinct positions, thanks to notches on its face that engage with the trigger’s sear, contributing to the gun’s iconic feel and functionality. The Colt SAA's power, accuracy, and ease of handling have kept it in demand well into the 21st century, primarily as a collector's item and symbol of the Old West.