I prefer to shoot Groundhogs up close and personal. I have always used PMC subsonics, and they work great. I bought several boxes and I am now told that they quit making them. Of all the 22lr rounds that I have used, Winchester Power Points kill them the best, bar non. I have several boxes of Aquila Super Maxes that I will try this year, CCI Stingers shot well in one of my rifles, but never worked well for me, go figure? Try the Power Points, I have never seen a 22 rifle that did not shoot them well.