I can't really compare the two from personal experience but I can't see these two peforming all that differently. It just could be that you are "luckier" with the
.30-06. I know you talked about some of the shot locations with the .308, what about the shot locations of the .30-06. Are the shots generally all pass throughs or not? What was the status of the animals vitals once you did recover and gut them, did you inspect exactly what the bullet hit and the damage it did?