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 more massive, they use a spring-wound mechanism to index the cylinder. Revolver cannons use a motor-driven revolver-like mechanism to fire. A Six Gun is a revolver that holds six cartridges. The cylinder in a six gun is often called a 'wheel', and the six gun is itself often called a 'wheel gun'. Although a "Six Gun" can refer to any six-chambered revolver, it is typically a reference to the Colt Single Action Army, or its modern look-alikes such as the Ruger Vaquero and Beretta Stampede. Until the 1970s, when older-design revolvers such as Colt Single Action Armys and Ruger Blackhawks