Do yourself a favor and order some JSB Diablo Exacts in the 18.13gr size. They're by far the best .22 cal pellets I've used on squirrels, rabbits, and other vermin. The Predator PolyMags work well too, as they are simply JSBs with the polymer tip, and they can be devastating on body shots, but they're not quite as accurate in the 30-50 yard range.
Also... squirrels are pretty damn tough when you're talking about pellet gun quarry. Shot placement is paramount, and small misses often lead to bad results.
Thanks for the tip, I have been meaning to order some of those from Pyramyd Air but have just not gotten to it yet. I am very glad to know there is better ammo out there.
I agree with you on squirrels being tough. I have seen the same thing happen when using SS HP out of a .22 LR, so I know they can take a good hit and still be going. Just was surprised that it took this much effort. Doubly surprising was that it was a young squirrel, we call them fryers, and not a tough old boar.
