27 CFR § 447.53 - Exemptions.
(a) The provisions of this part are not applicable to:
(1) Importations by the United States or any agency thereof;
(2) Importation of components for items being manufactured under contract for the Department of Defense; or
(3) Importation of articles (other than those which would be “firearms” as defined in 18 U.S.C. 921(a)(3) manufactured in foreign countries for persons in the United States pursuant to Department of State approval.
(b) Any person seeking to import articles on the U.S. Munitions Import List as exempt under paragraph (a)(2) or (3) of this section may obtain release of such articles from Customs custody by submitting, to the Customs officer with authority to release, a statement claiming the exemption accompanied by satisfactory proof of eligibility. Such proof may be in the form of a letter from the Department of Defense or State, as the case may be, confirming that the conditions of the exemption are met.