Just to clarify. CDP (car door penetration) is often discussed in the context of calibers vs barriers note: "pentration", not "glances off from an angled shot" What I haven't seen disscussed often is the "construction" of car doors. One round (any caliber) may sail through a "CD" (car door) with no problems and remain effective. Another round (any caliber) my not exit the other side of a CD or may exit without remaining effective. While I may be stating the obvious, again, I don't see it stated often at all: CD's are not "metal/plastic" skins. They contain many different materials making up many different structures. It's the (good or bad) luck of the draw whether or not any round short of 50 cal. gets through a door. There are too many variables like: 1. outer skin material used to construct the door 2. side impact barriers - most modern vehicles have a "cage-like" inner structure, some flat, some bar-like 3. window glass of varying materials and thicknesses 4. window regulator mechanisms of varying materials 5. electronic controls - accuators, connectors, etc with wiring 6. in-door speakers 7. inner door panels of varying materials 8. storage pockets that could contain a multitude of items of varying materials (just one of my door pockets contains a revolver speedloader, a full magazine, a metal flashlight, a window breaker and tire gauge) 9. spare change holders (my driver's door neatly stores $5 worth of metal coins) 10. door frames have different designs and different materials. 11. door locking hardware, rods, levers, connectors, etc. 12. some may even house side impact airbag devices "Car Door" does not translate "Door Skin". So, when I read discussions about "door penetration" the first thing that comes to my mind is "what kind of door and through what inside the door?". Most things just aren't as simple and static as they seem.