I think there's much gobblygoop going on here! Carbons are less straight than most aluninums so carbon's ability to transfere the said energy is less. We also have to remember that unless we are using cut on contact broadheads we probably have to rely on sectional density rather than just energy. Jack O'Connor and Bill Weatherby were marvelous story tellers and probably a realy good shots but mostly they had the time and resources to pick and choose thier animals and shots where they did not need sectional density. Bottom line, if you want penetration you have to go heavy. Does anyone know the weight of the arrow that killed an elephant? I think Dan does. And I think most of us know why it wasn't a high speed arrow. Most of us who can shoot at decent and honest ranges do not need a crutch like speed. This is supposed to be a sport about hunting with our whits not becoming equipment junkies or gaget guys.