I use only 12 guage 00 buck, though I have some slugs as well, though that is going to have some penentration issues. My thought is if you can't hit with 00 buck there are some serious issues. Birdshot is for birds for a reason. You are more likely to make an agressive person even angrier with birdshot.
Glock 17, 19, 20SF, 21C, 22, 26, 27, Glock E-Tool, Glock knife
Quod ego haereticus appellari sequere Jesum.