Md. Code, Pub. Safety § 5-123

(a) A licensee may not sell, rent, or transfer a regulated firearm until after 7 days following the time a firearm application is executed by the firearm applicant, in triplicate, and the original is forwarded by the prospective seller or transferor to the Secretary. (b) A licensee shall complete the sale, rental, or transfer of a regulated firearm within 90 days after the firearm application was stamped by the Secretary as not being disapproved. (c) (1) If the sale, rental, or transfer of a regulated firearm is not completed within 90 days after the firearm application was stamped by the Secretary as not being disapproved, a licensee shall return the firearm application to the Secretary within 7 days. (2) The Secretary shall void a firearm application returned under paragraph (1) of this subsection as an incomplete sale, rental, or transfer. (d) (1) (i) A licensee who sells, rents, or transfers a regulated firearm in compliance with this subtitle shall forward a copy of the written notification of the completed transaction to the Secretary within 7 days after delivery of the regulated firearm. (ii) The notification shall contain an identifying description of the regulated firearm, including its caliber, make, model, any manufacturer’s serial number, and any other special or peculiar characteristic or marking by which the regulated firearm may be identified. (2) The Secretary shall maintain a permanent record of all notifications received of completed sales, rentals, and transfers of regulated firearms in the State.