It has been my experience that it really doesnt matter what kind of .22 ammo you use when it comes to squirrel hunting. They are all gonna kill a squirrel if you shoot them in the head, sure some may be more accurate, but it's not like you're shooting something 500 yards away. Now, some ammo is much more dirty and you get a lot of misfires with them. I think the biggest factor is the quality of the rifle, and the quality of the optics if you choose to use them.