I never meant to insist that bullets don't pass through. I've had shots that left softball sized exit wounds, which means the bullet transered most of its energy inside the animal.
I think we all agree that if a bullet passes through too quickly and loses almost no energy inside, the animal was either too close and the bullet was too fast, it was too much gun, the wrong bullet composition, or it was poor target selection. I think we can also agree that when a bullet transfers most of its energy inside the animal, that it is what optimim bullet performance is all about. It's not War, it's Hunting.
Exit wounds aren't really necessary, but when they get huge and ugly, that is when your bullet did its job. Hit a rib or other light bone on the way in and you just might not get an exit wound. But the energy transfer (shock) will have done its job. Like I said before, a deer can be knocked completely off its feet with the proper distance, the proper weight bullet and the proper shot placement. An experienced hunter can find a rib to hit when looking through the scope, ribs aren't that hard to find. The closer the animal is, the bigger the bone has to be upon entrance.
The original question was asked about bullets passing through, let's say, the boiler room, as if it is a requirement for dropping and animal in its tracks. It is not. I prefer that bullets to either drastically slow down or come to a stop.
Face it, if the whole idea was passing through, then we don't need SP's, PSP's, RN's or FN's. We could all use FMJ's.
Hunting bullets are designed to slow down and begin to deform upon impact with tissue and transfer the energy. More hunters should adapt to this fact.
If I am wrong, I am more than willing to see the evil of my ways if somebody can explain it to me and have it make sense.