Brigadier General Benjamin Stone Roberts designed and patented a fall-block style of breech loading conversion to .58 Rimfire. Over the course of the decade after the Civil War, he was able to sell approximately 23,000 of these conversions. The work was done by the Providence Tool Company, and included two main patterns - the early short frame and the later long frame. This example is a short frame gun, probably from a 5,000-gun contract to Brazil.