I consider myself the local groundhog expert around here. I had to stop trapping them because I was doing too good, I have to have something to keep me busy in the summer, and if I got rid of them all, that wouldnt be any fun. Ive killed 2 with my 22lr at 300 yards. Took one down with a judo to the skull, he died instantly. However with that said I would probably not try it again. I often have thunderbolts 100 grains with a muzzy grasshopper behind the shaft, that way if I miss I wont loose the arrow, and that seems to work fine, still good penetration. If you penetrate 2 inches that would be like a foot into a deer. It will do damage. I personally like to use old 2 blade magnus stingers, they zip right through them with my 55# take down. If they are really a problem you should consider other methods. Such as trapping, or a rifle. But if there is no rush or anything to get rid of them, they will definatly give you a run for your money:)