Pub. L. 83-773, tit. V, sec. 504

Sec. 504. (a) For promotion purposes, seniority among Reserve officers is determined as follows: (1) Officers in any grade shall be senior to all officers in any lower grade; (2) Among officers of the same grade— (A) the officer with the longest period of promotion service in grade is the senior; (B) when seniority determined under clause (2) (A) is the same, the officer with the longest service as a commissioned officer (including service in the federally recognized National Guard or in a federally recognized status therein prior to 1933) is the senior; and (C) in all other cases the Secretary shall establish seniority. (b) A Reserve officer who is returned to an active status shall, for the purpose of promotion, if necessary, suffer loss of precedence, and a reduction in his years of promotion service in grade, so that one year after the date on which he is returned to an active status, the years of promotion service with which he is entitled to be credited for promotion purposes shall not be more than four, seven, or seven years of promotion service in grade if he is in the grade of first lieutenant, captain, or major, respectively.