Bill: I use # 5 shot for squirrel, mostly because it patterns better than #6 for some reason in my guns, and I like how they kill even at 30 yds. I think #6 shot would be adequate for most squirrels and rabbits, but would avoid using 7 1/2 or 8 shot on them I just don't think you get enough energy to drive the pellets through the fur and hide to insure a clean kill. You will knock them out of the tree, but they will often get up when they wake up after ten minutes or so, and God help you if they are in your game pouch, or the back seat of your car when this happens!