Only around 500 of the Model 1855 rifle-muskets were manufactured in .56 caliber with 31 5/16 barrels out of 9,310 military rifles manufactured in 1856-1864. It has a brass blade front sight, saber bayonet stud and bar on the right side at the muzzle (desirable), two barrel bands, sling swivels on the rear band and buttstock, a three-leaf rear sight, "COL. COLT HARTFORD CT. U.S.A." in the top strap groove, "PATENTED SEPT. 10th 1850" in one cylinder flute, "COLT'S PATENT/+/Nov. 24th 1857" on the left side of the frame, matching serial numbers visible on the upper and lower tangs, "56 CAL" on the left side of the trigger guard, and smooth stock and forearm with cleaning rod under the barrel and in the stock compartment.