It's the federal "Peaceable Journey" law. It allows you to travel through a state where you are not licensed, provided your journey starts and ends in a state where you may legally posses/carry/etc.
So, for example, if you're legal in Indiana and Pennsylvania, but not Ohio. You can pass through Ohio to Pennsylvania provided you don't stop (technically not even for fuel).
Generally, the gun must be unloaded and encased in a locked container or out of reach of the driver.
Some states require you field-strip the gun and to also have the magazines unloaded and stored separately from the gun.
This is one of the statements that is commonly misunderstood. The U.S. Code states: is readily accessible or is directly accessible from the passenger compartment.
So, storing itunder a heavy suitcase in the back seat, even if it is out of reach of the driver, it is still accessible from the passenger compartment.
So, lock it in your trunk.
I really wouldn't worry too much about stopping for gas. Refueling is a critical and necessary part of "transporting" your firearm. If you run out of gas, you will not be able to transport the firearm to the destination where you can legally have it, that is assuming that you can legally have it at your destination.
U.S.[/b] CODE Title 18, Part 1, Chap 44[/b]
[/i][/b] transportation of firearms.
Notwithstanding any other provision of any law or any rule or regulation of a State or any political subdivision thereof, any person who is not otherwise prohibited by this chapter from transporting, shipping, or receiving a firearm shall be entitled to transport a firearm for any lawful purpose from any place where he may lawfully possess and carry such firearm to any other place where he may lawfully possess and carry such firearm if, during such transportation the firearm is unloaded
, and neither the firearm nor any ammunition being transported is readily accessible or is directly accessible
from the passenger compartment of such transporting vehicle: Provided, that in the case of a vehicle without a compartment separate from the driver’s compartment the firearm or ammunition shall be contained in a locked container other than the glove compartment or console.