I have yet to see any slo-mo video of an arrow penetrating an animal's ribcage. Bigpapascout, if you have the visual proof that arrows flex when passing thru an animal's ribcage, I'd really like to see it. Otherwise, I consider that nothing but a myth.

I have seen so called tests that are set up specifically to 'prove' small diameter, light carbon arrows outpenetrate heavy, large diameter arrows. They've all been conducted on artificial mediums that are designed to stop an arrow by friction. I do not find it shocking in the least to learn that a large diameter arrow with lots of surface area is going to penetrate less in that kind of medium than a skinny arrow with little surface area. In fact, anybody with any sense would EXPECT those results. (That's why they 'tested' in that kinda stuff anyway - to produce 'shocking' results to baffle the unwitting and sell the advertisers' products.)

I'd like to see Ashby's study repeated using one specific brand of broadhead and bow as constants, with the variables being point of impact, arrow diameters, materials and arrow weights. With those results, we would be a long way toward blowing all the theory, mythology and outright BS totally out of arrow selection.