27 CFR § 478.36 - Transfer or possession of machine guns.
No person shall transfer or possess a machine gun except:
(a) A transfer to or by, or possession by or under the authority of, the United States, or any department or agency thereof, or a State, or a department, agency, or political subdivision thereof. (See Part 479 of this chapter); or
(b) Any lawful transfer or lawful possession of a machine gun that was lawfully possessed before May 19, 1986 (See Part 479 of this chapter).