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
Revolver powerful revolvers, utilizing the .500 S&W Magnum cartridge. Because the rounds in a revolver are headspaced on the rim, some revolvers are capable of chambering more than one type of ammunition. The .44 Magnum round will chamber the shorter .44 Special and shorter .44 Colt, likewise the .357 Magnum will safely chamber .38 Special and .38 Short Colt. In 1996 a revolver known as the Medusa M47 was made that could chamber 25 different cartridges with bullet diameters between .355" and .357". Revolver technology lives on in other weapons used by the military. Some autocannons and grenade launchers use mechanisms