Okay, I'm digging this post up from the grave I know. If your BH's are the same weight as your field tips then no it is not a spine issue. If say you are shooting 100gr field tips and 100gr Broadhead's then how could it be a spine issue if the field tips are shooting consistently? It's the broadhead's themselves that fly crappy. You aren't the first one to complain about this particular BH planing at past 30 yards and grouping poorly. The company tries to say that they will fly true to field tips with no "BH to Fletching tuning" but that is total horse pucky. Very few, if any, 2 blade fixed blades fly well without tuning. It's the nature of the beast with them.