The hit was NOT behind the diaphragm, or at most entered right on the edge, but the buck was quartering away enough for the bullet to get the top of both lungs--but NOT the liver, because the liver is on the other side of the body.
But the bullet did land HIGH in the lungs, not far below the spine. I did a bunch of research on lung wounds several years ago, including interviews with forensic ballisticians and veterinarians. The edges of the lungs have far smaller blood vessels than the center, especially in the area above the heart, and also less "air pressure." Consequently it not only takes longer for animals hit around the edges of the lungs to die, but depending on the extent of the wound they can even survive and heal up. It isn't uncommon, for instance, to kill elk that had been previously shot high through the lungs, just under the spine, and find the wound channel healed. An African PH I hunted with says it also happens with gemsbok, but he has never seen it with a kudu.
A monolithic bullet retaining all its petals doesn't make as large a wound channel as a more fragmenting bullet, but plastic-tipped monos usually expand enough to kill quickly when placed reasonably well. This hit was around the fringes.
Based on some experience, I'd guess the deer would have died quicker if hit in the same place with a bullet that at least partly fragmented, but that's just a guess. Have also seen animals hit with a bunch of other bullets, of all types, survive longer than they "should."
Makes sense to me!
Edit: Probably a slow twist barrel...
Thanks,
David
