So far (hehe!) I have a .22 and a .25. If I were to have something for just plinking with the family, I'd go with a .177 due to ammo price and availability. Our state law says that small game can be taken with .177 or .22. That said, for groundhogs it has to be at least .22. I'm still tossing around the bullpup idea and I'm split between a .22 and a .25. I see no reason to go bigger at the moment.