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 Army Model 1860 Colt Army Model 1860 The Colt Army Model 1860 is a cap & ball .44-caliber single-action revolver used during the American Civil War made by Colt's Manufacturing Company. It was used as a side arm by cavalry, infantry, artillery troops, and naval forces. The Colt 1860 Army uses the same size frame as the .36 caliber 1851 Navy revolver. The frame is relieved to allow the use of a rebated cylinder that enables the Army to be chambered in .44 caliber. The barrel on the 1860 Army has a forcing cone that is visibly shorter than that of the 1851