Unless someone is shooting at you from inside a car or using the car as a weapon then you have no need to be wanting to shoot through a car door. I would be willing to bet you will end up in jail for a long time.

Sometimes I went into somewhere I couldn't be carrying I had pushed my gun under the seat. I get home and forget to get the gun then I realize it I go out and get it. I don't ever like leaving a gun in my car. A thief just might find it and use it on me.

As far as carrying a rifle in my truck I decline doing that. In a bad situation I would possibly be dead before I could get to the rifle to protect myself. Perhaps a 8-10" barreled revolver large caliber might be considered but then again I would not feel safe leaving it in my truck at anytime and concealing on myself a long barrel handgun when I go into a store isn't easy.

I would think a 357 0r 44 magnum revolver should be able to do whatever you are wanting a gun to do. Don't expect to be able to hear much if you fire one of those off while in a car. Well about any gun for that matter.