I remember reading somewhere in the regs that broadheads must contain a razor like edge. I don't think you will be able to get an esge like that on a rock...but try it if you want. I too would suggect mailing a letter directly to the head commissioner dude. That way you know what ever he responds with is the actual answer. If it is ok, thenI suggest keeping that letter with you when ever hunting so if you are questioned, then you have proof that you are ok.