How about this why would someone give up energy/momentum (Which kills the animal) for a trivial amount of speed? I just don't see it.
Well E when is enough.... enough? 400 grains at 80 ft/lb isn't enough? Where do you stop?
Ok lets add 210 grains and subtract 70fps....
SO 610 grains at 230 fps only yields 72 ft/lb of KE
Perhaps I should shoot that setup instead from what you are saying?