U.S. M1816/1822 muskets manufactured at Whitney's Armory were identical to those produced at U.S. Armories at Springfield and Harpers Ferry. Overall length was 57.75". The 42" long, .69-caliber smoothbore barrels were finished with a browning solution until 1831; after that date metal was left in polished "bright". Stock and lock reflect Whitney's earlier attempts to impart his design elements into the U.S. patterns. Stock had low comb of his M1812 musket and lock incorporated rounded cock and round bottomed brass pan that he had championed from French M1777 musket. Lock markings varied during the period that this arm was produced, though all were marked on the pointed tail with a vertical stamp: "NEW HAVEN" arced around date (1825-1830), or in three vertical lines: "NEW / HAVEN / (date: 1831-1842)". Those made between 1825 and 1830, under direct supervision of Whitney's nephews, bore two line mark "U.S. / P. & E.W. BLAKE" forward of cock; those made from 1830 to 1837 bear "U.S" over "E. WHITNEY" with a crossed arrow and olive branch between; after 1837, crossed arrow and olive branch motif was eliminated in favor of the simple two lines. In addition to Whitney Armory's federal contracts, Whitney executed at least one contract with the state of South Carolina in mid-1830s for an estimated 800 to 2,000 muskets. Basically identical in configuration to federal contract muskets, South Carolina muskets were distinguished by the substitution of "S.C." for "U.S." over "E. WHITNEY" stamp on the lockplate. They also bear state ownership mark "So. CAROLINA" on top of the barrel. Due to their relative rarity and Confederate usage (especially if altered to percussion by means of a brazed bolster), South Carolina contract arms should bring a considerable premium.