I won' t go into my entire tuning process, but will suffice to say that it is similar to Fletchhead' s procedure. I have had similar results with broadheads. When a properly spined shaft is properly tuned to the bow, the broadheads always group right with the field points. I shoot mechanicals, but I always check POI with fixed Muzzy' s.

I' m very sure that if broadhead tuning is done correctly, the same results will be attained. I would advise shooting through paper or bareshaft tuning to ensure good spine though. Broadheads can group well with a slightly underspined arrow, but the slightest form flaw will make them impact differently and I feel that an underspined arrow will decrease penetration. I haven' t seen any type of broadhead tuning that will ensure good spine. It may be possible, but I haven' t seen it. If you only tune with BH' s, then stay on the stiffer end of the spine range as you will have much less trouble with a slightly stiff arrow.

I agree with Fletch totally that the main reason for BH' s and FP' s not grouping together is spine. An underspined arrow CAN tune perfectly with FP' s, but will impact differently with BH' s.

In short, if you' re getting perfect bullet holes and your FP' s are impacting differently than your BH' s, check the spine of your shafts. It' s a good bet, you are underspined.