as far as a rabbit goes, I have 2 rules.
1) put the same lead on it that you a bird in the air, don't let the fact it is on the ground screw you up.
2) if it jumps, that is when I try and shoot it. That is when the target is as stable as it is going to get

I may not be smart but I can lift heavy objects

I have a shotgun so I have no need for a 30-06.....