re: Shooting through a car door. From inside.

I would not advise this.

This was actually my 8th grade science fair project. I took a 9mm, .40 and .45 and shot each one at an old car door from different distances and then shot each one at a windshield at different angles. I forget exactly which angle it was, but passed a certain angle the 9mm simply deflected off the windshield. I don't remember much about what happened with the car door except that most didn't make it through, but that was from a distance. However, I took the car door apart after (this was an older car door) and there was a ton of metal inside that would easily stop a bullet.