Pub. L. 83-773, tit. III, subtit. A, sec. 306
minimum service in grade
minimum service in grade Sec. 306. (a) Except as provided in sections 317 (b) and 319, a Reserve officer in the grade of second lieutenant may not be promoted, or federally recognized, in the next higher grade, until he has three years of promotion service. (b) A Reserve officer, other than an adjutant general or assistant adjutant general of a State, Territory, or the District of Columbia, in a grade above second lieutenant, may not be considered for promotion by a selection board or examined for Federal recognition in the next higher grade until he has the following minimum years of promotion service: Grade Minimum years of promotion service First lieutenant 2 Captain 4 Major 4 Lieutenant coloneel 3 Colonel 2 Brigader general 2