You may remember last year I shot a doe high through the lungs at around 90yds from my X7 with a 300SW Bonded. I shot just underneath the spine, the bullet did not expand AT ALL but put a neat hole through the top of both lungs.

The deer dropped like a ton of bricks and never flinched, DOA before she ever had a chance to feel the effects of the lung punctures.

I have seen this several times, hits close to the spine resulting in instantly dead deer despite seemingly not enough damage. What I think is happening is that the shock of the bullet passing that close is enough to "short-circuit" the neurological signals or even perhaps cause enough damage to permanently shut off the signals at that spot.