I think I'd be okay in Maryland courtesy of 18 USC 926A
It basically says that if you're going from point A where you can legally possess a certain firearm to point B where you can legally possess it, then as long as it's unloaded and not in the passenger compartment (or unloaded, in a locked container if you're in a car that doesn't have a trunk), then federal law says you have the legal right to do so.
Do you want to think you'll be okay or do you want to know you'll be okay?
then federal law says you have the legal right to do so
Have you decided exactly how much of your time and money you want to spend arguing the point with some pencil di**** gun hating DA in Maryland or DC?
L