Mass. Gen. Laws ch. 131 § 63
A person, other than the director of law enforcement, his deputy directors of enforcement, chiefs of enforcement, deputy chiefs of enforcement, environmental police officers, deputy environmental police officers, warden and members of the state or local police in areas over which they have jurisdiction, special officers or persons charged with the protection of persons or property while acting in the discharge of their respective duties, as such, and paraplegics as provided in section sixty-five, shall not, except upon land owned or occupied by him, have in his possession or under his control in or on any motor vehicle or aircraft a loaded shotgun or rifle, nor shall he have in his possession or under his control in any motorboat a loaded shotgun or rifle unless authorized by the director in regulations relating to the hunting of migratory waterfowl; and any person shall, upon the demand of any officer authorized to enforce this chapter, display for inspection any shotgun or rifle in his possession or under his control in a motor vehicle, aircraft or motorboat while not on property owned or occupied by him.
Mass. Gen. Laws ch. 131, § 63