Calhoun 42g Double HP gets my vote, very often you shoot the ground squirrel and he is just GONE! I shot a of the 50g Blitz, tnt, Speer 52, and all poly tips of which the Sierra Blitz king is the most destructive in the 50g Weight.

That large HP plus the extra speed on the 42g bullet really gets those little squirrels fly'en when the bullet is going 3650-3800 fps+ out of a 223.