MS9557E, MILITARY STANDARD: BOLT, MACHINE-DOUBLE HEXAGON EXTENDED WASHER HEAD, CORROSION AND HEAT RESISTANT STEEL, .250-28 UNJF-3A (02 SEP 1993) [SUPERSEDED BY SAE-AS9557].
MS9557E, MILITARY STANDARD: BOLT, MACHINE-DOUBLE HEXAGON EXTENDED WASHER HEAD, CORROSION AND HEAT RESISTANT STEEL, .250-28 UNJF-3A (02 SEP 1993) [SUPERSEDED BY SAE-AS9557].