This is a 3in load from 10 feet, and 20% gelatin. The buckshot barely goes 10in into the gel. That surprises me as I thought it would penetrate a little deeper. Of course, the strength of a car door will vary. But it's a good reference.
I remember an expert saying Brennekke slugs are for windshields and car doors (I think it was Evan Marshal).
I was thinking of switching my trunk gun load to 15 pellet 00 buck but after watching this I think I will keep it at 000.