Look at the Federal law....
[18 U.S.C. 922(b)(3)]
(b) It shall be unlawful for any licensed importer, licensed manufacturer, licensed dealer, or licensed collector to sell or deliver...
...(3) any firearm to any person who the licensee knows or has reasonable cause to believe does not reside in ... the State in which the licensee’s place of business is located, except that this paragraph (A) shall not apply to the sale or delivery of any rifle or shotgun to a resident of a State other than a State in which the licensee’s place of business is located if the transferee meets in person with the transferor to accomplish the transfer, and the sale, delivery, and receipt fully comply with the legal conditions of sale in both such States (and any licensed manufacturer, importer or dealer shall be presumed, for purposes of this subparagraph, in the absence of evidence to the contrary, to have had actual knowledge of the State laws and published ordinances of both States), and (B) shall not apply to the loan or rental of a firearm to any person for temporary use for lawful sporting purposes...
Then look at state law:
790.28 Purchase of rifles and shotguns in contiguous states.--A resident of this state may purchase a rifle or shotgun in any state contiguous to this state if he or she conforms to applicable laws and regulations of the United States, of the state where the purchase is made, and of this state.
