One thing to consisder when talking penetration in a foam target is the heat generated by a carbon arrow. Why do carbons need lube? Because the heat causes them to stick. I pull an arrow and it's usually still warm after a few minutes, and may have foam sticking to it. The heat is caused by friction, which more quickly slows the arrow. Yet the carbons still go in deeper, all things being equal.
Phil.
"Could you guys be quiet, my dad's trying to shoot."<img src=icon_smile_shock.gif border=0 align=middle>