Went out with a buddy of mine and his wife a couple weeks ago for pronghorn doe/fawn opener. 153 A-Tip out of a 6.5 PRC, running around 2940? If I recall correctly. Range was 580 yards, and we're at around 7000 ft elevation, so 2375-2425 fps retained velocity. Shot was on a large fawn pronghorn.
At the shot, the fawn didn't react, I actually thought it was a miss at first, she ran about 100 yards and started slowing down, and started to limp, and was apparent she had been hit. We had the shooter prepare for another shot, but the fawn layed down in the alfalfa. She got up, and layed back down several times, never giving enough time for a second shot. She would lay her head down, pick it up, lay it back down again, and so on. The shooter took a couple shots for the head, but was just barely off the mark, also didnt help that she was only using a 3-9x SWFA.
So, we started walking towards her to get closer and put a finishing shot. At around 400 yards, she got up again, then layed down before we could put another round in her. We kept closing distance until we were around 75 yards, they were able to put a round through the base of the skull to finish her off and not waste any meat. The entire ordeal from first shot to last was 10, maybe 15 minutes or so.
Upon walking up to her, we were not sure what to expect. However, shot placement was perfect, just above heart level, right behind the elbow perfectly in the pocket, exit was about 1.5 - 2" behind as she was very slightly quartering to, excellent double lung hit. When we opened her up, there was zero expansion, none. 6.5 cal entrance and exit. There was nothing other than rib and lungs hit, however when she was layed on her side, the penetration path was 7-8", maybe more, plenty of distance for expansion to initiate. The lungs looked nearly untouched, with maybe a 1" diameter bruise around the bullet pin hole path.
This is only an example of one, and it was on light game, however it was still a failure. I will also say that there was two other pronghorn taken with this same set up, on one neck bone was hit on a full sized doe, and another was hit a little far back through the back of both lungs but also the front of the paunch, and both were devastating.
Personally, for testing bullets, I put more weight in hits that don't contact much bone, or even stomach, stomach contents tend to be denser than lungs and help initiate expansion, and hitting bone can be decieving, as much of the damage done is likely not even from the bullet but the secondary projectiles. I have shot coyotes with FMJ 223 ammo that left incredible wounds, because I hit the shoulder. Actually, broadside behind the shoulder through both lungs is likely the lightest media in a game animal to pass a bullet through. Thin ribs, meat behind the shoulder, and lungs do not offer much resistance for a bullet to expand in when compared with shoulder meat, bone, liver, stomach contents, and so on.
Member PNWGator has detailed photos, if he sees this thread hopefully he posts some up.