Material is 4140 steel, mil-s-5626or ams 6382, chrome plate per mil-p- 6871 type 2, diameter is 0.7469 in. Min. And 0.7480 in. Max. After chrome plating, inside dia. Is 0.623 in. Min. And 0.635 in. Max., heat treat 160- 180, 000 psi uts per mil-h-6875, length is 4.478 in.