In every report ever published by Ashby he has unequivocally stated that perfect arrow flight is the NUMBER ONE factor in arrow penetration. Not UEFOC, not threshold weights, not broadhead design, not arrow shaft diameter. Holy mother of God folks read what the man is saying before making uninformed, uneducated, replies. His "recommendations" are how to increase your penetration on marginal hits, through HEAVY bone, assuming you have a well tuned set up. For guys hunting turkeys, white-tails, javelina etc. it probably doesn't amount to a hill of beans. For guys hunting, Moose, Elk, Big bear, Bison, African and Australian buff, etc. It may have more importance. I for one have bought into his findings, maybe it makes me right and smart, maybe it makes me wrong and not so smart. What it does make me (with 100 percent certainty) is more confident in the ability of my equipment to do the job I'm asking of it, and THAT may be the most beneficial result of all this. Thanks Doc.