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 Paterson Starting in 1839, however, a reloading lever and a capping window were incorporated into the design, allowing reloading without requiring partial disassembly of the revolver. This loading lever and capping window design change was also incorporated after the fact into most Colt Paterson revolvers that had been produced from 1836 until 1839. Unlike later revolvers, a folding trigger was incorporated into the Colt Paterson. The trigger only became visible upon cocking the hammer. A subsequent patent renewal in 1849, and aggressive litigation against infringements, gave Colt a domestic monopoly on revolver development until the middle 1850s. Early Colt literature and