45-cal. Single Action Army—which was initially ... replacing it with Colt’s New Army & Navy double-action revolver chambered in .38 Long Colt—a smokeless-powder cartridge with roughly ...

The Colt Single Action Army revolver, introduced in 1873, became a symbol of power and American expansion, used by both outlaws and lawmen on the frontier.

In the 1870s, Colt needed a double-action revolver design to compete with many of the emerging double-action revolvers on the market, particularly a number of competitors in Great Britain.