Designed by Gilbert Smith, the production of this breech loading percussion carbine was almost entirely consumed by government contracts, with limited numbers going to the civilian market. Dovetail blade front sight and folding leaf rear sight absent of yard markings. Breech loading action with barrel release latch inside the trigger guard, freeing the barrel to pivot downward. Standard markings on the left side of the frame, "MANUFACTURED BY / AM'N M'CH'N. WKS / SPRINGFIELD MASS", agents' names "ADDRESS / POULTNEY & TRIMBLE / BALTIMORE U.S.A." and "SMITH'S PATENT / JUNE 23, 1857". Casehardened hammer and action with a saddle ring and bar mounted on the left side of the frame with a smooth forearm and straight grip walnut stock with a steel buttplate. The left side of the barrel has a U.S. Government inspector's initials of "LFR" with a boxed "LFR" and oval script "JH" cartouche on the left side of the stock wrist behind the sling bar.