Mich. Comp. Laws § 750.231a

Sec. 231a. (1) Subsection (2) of section 227 does not apply to any of the following: (a) To a person holding a valid license to carry a pistol concealed upon his or her person issued by his or her state of residence except where the pistol is carried in nonconformance with a restriction appearing on the license. (b) To the regular and ordinary transportation of pistols as merchandise by an authorized agent of a person licensed to manufacture firearms. (c) To a person carrying an antique firearm, completely unloaded in a closed case or container designed for the storage of firearms in the trunk of a vehicle. (d) To a person while transporting a pistol for a lawful purpose that is licensed by the owner or occupant of the motor vehicle in compliance with section 2 of 1927 PA 372, MCL 28.422, and the pistol is unloaded in a closed case designed for the storage of firearms in the trunk of the vehicle. (e) To a person while transporting a pistol for a lawful purpose that is licensed by the owner or occupant of the motor vehicle in compliance with section 2 of 1927 PA 372, MCL 28.422, and the pistol is unloaded in a closed case designed for the storage of firearms in a vehicle that does not have a trunk and is not readily accessible to the occupants of the vehicle. (2) As used in this section, "antique firearm" means either of the following: (i) A firearm not designed or redesigned for using rimfire or conventional center fire ignition with fixed ammunition and manufactured in or before 1898, including a matchlock, flintlock, percussion cap, or similar type of ignition system or replica of such a firearm, whether actually manufactured before or after 1898. (ii) A firearm using fixed ammunition manufactured in or before 1898, for which ammunition is no longer manufactured in the United States and is not readily available in the ordinary channels of commercial trade.