Straightarrow, we are probably thinking the same using different words. What I meant was that I could have the most perfectly tuned bow, and still have problems throwing broadheads, because the arrow itself (not just spine), was not airodynamically (I'm looking for another word but can't find one) set up for optimum broadhead flight. For instance, moving from a non-helical to a helical, or putting an extra fletching on (like I did), having optimum FOC, etc.