My main home defense gun is a 20 ga. SxS with #4 buck in the holes (the biggest shot I've been able to find for a 20). Besides being more than a little bit lethal, there's something about looking down 2 big black holes that will make a crook's knees shake.
#2 buck is available in a 3" 20 pellet load from Federal. #3 buck in a 20 pellet load is the standard in 2 3/4" 20 gauge.
