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 Dragoon Revolver days. With the addition of a loading lever this evolved into the 1849 pocket revolver (see Colt Pocket Percussion Revolvers). The Dragoon was produced because of the problems seen with the fielded Colt Walker revolvers, namely, the Walker's heavy weight, four and a half pounds, making it suitable only for use as a saddle-mounted revolver, the Walker's propensity for cylinders exploding on occasion when fired (due to the chambers being loaded with too much powder), and the Walker's habit of dropping the loading lever upon discharge, locking up the revolver action in the middle of combat. The Colt Dragoon Revolver