At the outset of the American Civil War, the wealthy inventor and expert shot Hiram Berdan initiated the setting-up of sharpshooting units in the Union Army; these units would be tasked primarily with open-order skirmishing, but also with long-range, accurate shooting. Initially, it was envisaged that the M1855 Colt revolving rifle would be the weapon employed by these specialists. Available in .36, .44, and .56 caliber, the M1855 swiftly earned...