Probably not what you want to hear, but for in house SD there isn't a better platform than a shotgun loaded with mid size shot, say #4-#6. I like a pump, YMMV. If you can't whack a bad boy with 5 shots, well, I don't know what to say. Ladies and 20 bores go together like divorce and lawyers.
The ranges are very short in a house, walls are thin and the last thing you want to do is kill someone in an adjacent room accidentally.
birdshot is just wrong. You want to kill the fellow, not just pepper him. I load 00 Buck. You don't see any cops using bird shot. Or the military.
