FEDERAL LAW ON TRANSPORTATION OF FIREARMS
A provision of the federal law known as the Firearms Owners’ Protection Act, or FOPA, protects those who are transporting firearms for lawful purposes from local restrictions which would otherwise prohibit passage.
Under FOPA, notwithstanding any state or local law, a person is entitled to transport a firearm from any place where he or she may lawfully possess such firearm to any other place where he or she may lawfully possess it, if the firearm is unloaded and locked out of reach. In vehicles without a trunk, the unloaded firearm shall be in a locked container other than the glove compartment or console. Ammunition that is either locked out of reach in the trunk or in a locked container other than the glove compartment or console is also covered. FOPA also seems to provide for necessary stops, like gasoline and rest.
Travelers should be aware that some state and local governments treat this federal provision as an “affirmative defense” that may only be raised after an arrest.