I can't imagine there would be anything left of a squirrel after getting shot with a 357.
Thats why I stated in my earlier post I have round ball loads for my 357 that are low velocity. They are only good for about 40 yards or a little more. For squirrels and rabbits and other small game you don't need a lot of speed or range. My loads duplicate the old Rook & Rabbit type loads.
Learn to reload and almost any center fire rifle can be used for small game. This is a good article on doing so.