Your last sentences regarding the .45/70 - are you referring to a Trapdoor Springfield's loads, Model 86 or 71 Winchester or Marlin loads, or a Ruger #1 or bolt gun's loads? It does make a difference.

The bolt gun and Ruger can make 2,050fps with 500gr. solids.

What are the 'actual' chronographed ballistics of the .470? Granted the larger bullet of the .470 does or should have an effect - with equal bullet integrity, of coruse, but I think we might have a stalemate there on charging game.

I agree that any formula leaves too much out & that none work all the time.

Coming up with them, ie: inventing formulas, and spouting to all who will read, does pay the gun-writer's bills though - the more diverse the formula, the more words required and the greater the sum of the check.