BTW...the ideal hit is a double lung with the head making contact near verticle and not hit a rib...and exit without hitting a rib. Not because of penetraition...but that the deer will not even know its hit.
I've done this several times with Delta 4 blades, and its part of the reason I have such a short recovery average as the deer only take a couple of bounds and look back to see what happened. I've had them fall over right there, I've had them start to walk off and fall over after a few yards...and I've even had them pick up another acorn and drop while they were chewing.