MIL-S-63348A (NOTICE 1), MILITARY SPECIFICATION: SUBMACHINE GUN, 5.56MM, PORT FIRING, M231 (24 AUG 1988) [NO S/S DOCUMENT]., MIL朣-63348A(AR), dated 20 August 1981, with Amendment3, dated 3 August 1981, has been reviewed and determined to be valid for use in acquisition.