MS21284B, MILITARY STANDARD: BOLT, MACHINE - STEEL, DOUBLE HEXAGON, EXTENDED WASHER, .500-20 (MIL-S-8879 THREAD) (17 SEP 1963)
MS21284B, MILITARY STANDARD: BOLT, MACHINE - STEEL, DOUBLE HEXAGON, EXTENDED WASHER, .500-20 (MIL-S-8879 THREAD) (17 SEP 1963).