RE: carbons and recurves???
I agree with Arthur P about the value of arrow weight in penetration. AP and others are have hashed this penetration issue out time and time gain on another forem.
There are other issues besides arrow speed and weight that also come into play and effect penetration. Like arrow drag through the animal. Factors like the broadhead and shaft design that you are shooting. I've found that I gotten better penetration from a two blade cut to the tip over say a snuffer design. The snuffer has greater drag, and in my case should be shot at thinner skinned animals like whitetails, not hogs unless I'm shooting a heavier poundage bow. If you shoot a tapered carbon shafts like the Arrow Dynamics Traditionals the head opens up channel where the decreasing sized shaft slides through with less resistance.