There is some leeway with regard to trucks, usually behind the seat is acceptable due to the lack of a trunk. But as JN01 said, box magazines for rifles or other long guns cannot be loaded. Pretty much same rules as a non-ccw holder would have for a pistol - ie, gun unloaded and encased, ammo in a separate compartment, etc & so forth.
Any centerfire firearm using a magazine that holds over 30 rounds is considered a machine gun by the State of Ohio.
Was most definitely not aware of that!
Any idea where a citation for that might be found?