1825 ca. - Percussion-cap guns are in general use. 1830 - The back action lock appears. 1835 - The first Colt revolver. Samuel Colt developed the first mass-produced, multi-shot, revolving firearms.

And by the time of Jesse's bank robberies in the early 1870s, the weapon of choice was the Colt .45 Peacemaker, which combined the bullet, gunpowder, and percussion cap in one cartridge and was ...