10 U.S. Code § 520 - Limitation on enlistment and induction of persons whose score on the Armed Forces Qualification Test is below a prescribed level

(a)
The number of persons originally enlisted or inducted to serve on active duty (other than active duty for training) in any armed force during any fiscal year whose score on the Armed Forces Qualification Test is at or above the tenth percentile and below the thirty-first percentile may not exceed 20 percent of the total number of persons originally enlisted or inducted to serve on active duty (other than active duty for training) in such armed force during such fiscal year.
(b)
A person who is not a high school graduate may not be accepted for enlistment in the armed forces unless the score of that person on the Armed Forces Qualification Test is at or above the thirty-first percentile; however, a person may not be denied enlistment in the armed forces solely because of his not having a high school diploma if his enlistment is needed to meet established strength requirements.