27 CFR § 478.96 - Out-of-State and mail order sales.
(b) A licensed importer, licensed manufacturer, or licensed dealer may sell a firearm that is not subject to the provisions of § 478.102(a) to a nonlicensee who does not appear in person at the licensee's business premises if the nonlicensee is a resident of the same State in which the licensee's business premises are located, and the nonlicensee furnishes to the licensee the firearms transaction record, Form 4473, required by § 478.124. The nonlicensee shall attach to such record a true copy of any permit or other information required pursuant to any statute of the State and published ordinance applicable to the locality in which he resides. The licensee shall prior to shipment or delivery of the firearm, forward by registered or certified mail (return receipt requested) a copy of the record, Form 4473, to the chief law enforcement officer named on such record, and delay shipment or delivery of the firearm for a period of at least 7 days following receipt by the licensee of the return receipt evidencing delivery of the copy of the record to such chief law enforcement officer, or the return of the copy of the record to him due to the refusal of such chief law enforcement officer to accept same in accordance with U.S. Postal Service regulations. The original Form 4473, and evidence of receipt or rejection of delivery of the copy of the Form 4473 sent to the chief law enforcement officer shall be retained by the licensee as a part of the records required of him to be kept under the provisions of subpart H of this part.
(1) A licensed importer, licensed manufacturer, or licensed dealer may sell or deliver a rifle or shotgun, and a licensed collector may sell or deliver a rifle or shotgun that is a curio or relic to a nonlicensed resident of a State other than the State in which the licensee's place of business is located if -
(2) For purposes of paragraph (c) of this section, any licensed manufacturer, licensed importer, or licensed dealer is presumed, in the absence of evidence to the contrary, to have had actual knowledge of the State laws and published ordinances of both such States.