I've seen little difference between carbons moving at high speeds and aluminum moving at more moderate speeds in terms of penetration. All the archery ballistics programs I've punched numbers into actually show very little difference in KE inside 50 yards between slow and heavy or fast and light from the same bow. Shot placement and broadhead design are much more important. I will definitely say that my experience has shown carbon to be much more durable for hunting. One season, I arrowed 4 deer with a single carbon arrow. I just kept replacing the blades in the Thunderhead 100 and putting it back in the quiver.