I guess field-dressing and butchering is sorta doing a post-mortem, right?
In comparing damage from a cross-body shot to a deer's chest, it seems to me that my '06 hits had the serious tissue damage beginning about 1/3 to 1/2 of the animal's width, and then blowing on out with a fairly large exit wound.
With the .243, it started at maybe 1/4 of the width. No exit wound, but a (roughly) six-inch sphere of destruction.
Now, these were mostly smallish bucks, field-dressing at 90 to 110 pounds, and I'm not saying it was this way on every shot.
I'm guessing the 85-grain .243 bullets opened up more quickly and/or "blew up" inside the animal. Well inside.
I note that Charles Whitman had a one-shot kill at 420 yards with his 6mm Remington, from an upper-right hit to the chest. The bullet hit a rib on the way in, deflected downward through the lung and into the abdominal cavity.
Art