Designed by Gilbert Smith, the production of this breech loading percussion carbine was almost entirely consumed by government contracts. The left side of the frame is marked "MANUFACTURED BY/AM'N M'CH'N. WKS/SPRINGFIELD MASS", "ADDRESS/POULTNEY & TRIMBLE/BALTIMORE U.S.A." and "SMITH'S PATENT/JUNE 23, 1857". The left rear barrel flat has inspector's initials "LFR". Blade front sight and folding leaf rear sight absent of yard markings. Casehardened hammer and action with a saddle ring and bar mounted on the left side of the frame, and mounted with a smooth forearm and straight grip walnut stock with a steel buttplate and a script letter cartouche stamped on the left side of the stock wrist.