American or British Brown Bess Fusil Socket Bayonet. The face is marked with a "5" or "6", no other markings are seen. It is straight, age spots with small pitting scattered throughout, and has some surface rust. Length of the blade measures 12" (15/16" wide x 7/16" thick) and the bayonet is 15 1/4". The socket is 3 1/4". The muzzle hole is 13/16", and 3/4" at the other end.