600 yards and you want to humanely bring down a moose? Where I live in Alaska that is ridiculus.
But I know some guys that use a 50bmg with a .375 sabot and they take down bears at that range.
The retained kinetic energy needed to bring down large game at that distance is so far gone that on a thick hide it will just make the amnimal suffer. Small game sure, but not big game.
No.