This is a nice looking bayonet. This one started out life as the classic model 1855 socket bayonet for the Civil War .58 caliber Springfield or contract rifles. It has the full-length blade that is in beautiful shape. At the base of the blade it has the "US" marking with an inspector "S" below the US. The socket is what separates it from t he standard Civil War bayonet. After the Civil War, the diameter of the trapdoor Springfield rifle was smaller so they needed to reduce the size. This version had the socket sliced along the top and squeezed down to fit the smaller barrel. The inside diameter of the socket measures .745 at the rifle side and .73 at the blade side. The lockring is present but it has had the stud removed so now it turns freely. This one displays superbly and is about 1/2 of the price of what an original untouched Civil War bayonet brings these days.