bfr... I used to shoot heavy loads on deer, as well. I eventually figured out it wasn't necessary. If my bullet puts 2 holes in the deer and punctures lungs and/or heart on the way through, the deer will die in short order. Much like your 17 water jugs demonstrated, most of the energy of those 325 gr bullets leaving the muzzle at 1300+ fps was expended long after perforating the deer I was shooting at. I eventually realized that a 265 gr bullet stepping out at 900-1000 fps would do the job just as well, and did a lot less damage to my hand.
The FBI protocol for defense/service loads is 12-14 inches. They chose that penetration depth for a reason: these bullets/loads won't shoot through the torso of a human being, averting the liability of subsequent perforation of bystanders downrange. As hunters, we know that having 2 holes in what we are trying to kill is better for tracking game to the location of the dead animal. When shooting humans, tracking to find the carcass ain't quite as important. So I can live with the FBI's penetration model, and that is why I don't carry WFN loads in my carry pistol(s). I should note that when I'm out in the field or mountains, where overpenetration is a virtue rather than a liability, my sidearm is (usually) stoked with flatnose cast bullets.
Good and even a heavy bullet in a .45 Colt slower will kill anything on earth. It is not velocity but where energy is applied and too fast does not mean deader. The fact is I have revolvers that shoot too fast like the 45-70 BFR and it will lose deer because 1630 FPS makes it a stick hole. Then I found a WFN does not work better then a WLN. There is a pressure wave from the meplat that will move tissue out of the way of the bullet and will collapse back so the big meplat theory is not true. Slow the big meplat and it will work better.
