I’m wondering if the ‘Castle Doctrine/Stand Your Ground’ covers shooting thru a door at an assumed threat? 2-3 coming thru at a time presents a lot of ‘centermass’, doesn’t it? LOL.
I would be worried about multiple rounds traveling beyond your residence and perhaps striking a neighbor's home across from yours. A better defense would be to see your target and shoot accordingly. Not a good idea to shoot through the door, especially multiple times.
Might be an idea to keep a pressurized party air horn (of the variety used at sporting events), and blast it near the door or out an open window. That might be enough to frighten off the perp, and also alert neighbors to take a peek. (I keep an air horn handy just in case.)