Colt Walker of Texas had been the major purchaser of the early Paterson Holster Pistol (No. 5 model), a five shot cal .36 revolver, and Samuel Walker became familiar with it during his service as a Texas Ranger. In 1847, Walker was engaged in the Mexican-American War as a captain in the United States Mounted Rifles. He approached Colt, requesting a large revolver to replace the single-shot Aston Johnson holster pistols then in use. The desired .44-.45 caliber revolver would be carried in saddle mounted holsters and would be large enough to dispatch horses as well as enemy soldiers. The Colt Walker
Colt Single Action Army but brought it back due to popular demand. The revolver was popular with ranchers, lawmen, and outlaws alike, but as of the early 21st century, models are mostly bought by collectors and re-enactors. Its design has influenced the production of numerous other models from other companies. The Colt SAA "Peacemaker" revolver is a famous piece of Americana. The original length of the barrel, issued to the U.S. Cavalry, was inches (with an overall length of 13 inches). Bound by the Rollin White patent () and not wanting to pay a royalty fee to Smith & Wesson, Colt could not begin