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 ).