Material: steel, carbon 1015-1025 per astm 108; protective finish: black oxide per mil-c-13924 class 1; heat treatment: carburize and harden per mil-s-6090 and mil-h-6875 to case depth 0.035in-0.045in; surface hardness: rockwell c58-62; length of 3.50in; diameter of 3.10in; diameter of 1.75 inch