Sounds like some wobble problems. Even if you have to take one head at a time and screw it into every arrow you have, its worth it. Also double check every little thing you can, fletch clearance, every thing. BH's make the tiniest problems and magnify them. I've just gone thru this same thing. Slow careful wobble check will keep you from going in circles. Once you get good grouping w/ BH's then you can move the rest to get them to shoot with FP's