RE: Why would you want a pass through??
This season I kiilled two bucks, on the first one I recovered my bullet. This deer ran about 30 yards and I was able to find him, even though there was no blood trail. Had he run much more I may not have recovered him at all. On the second buck, my bullet failed to expand. The exit was no larger than the entrance. This deer ran 75 yards or so through some very thick pines and briars. He did not leave any blood trail. Tracking him in the dark was nearly impossible and I feel very lucky to have found him!
Both these bucks were dead the instant they were shot, they just happened to run! Most heart/lung shots do run a little ways.
I know the theory of having a bullet expend all its energy inside an animal, but even when that happens the animal may run 100 yards are so before dropping. That is why I'd rather a bullet that expands AND exits, a good blood trail can mean the difference between venison on the table and buzzard bait!