ORIGINAL: Straightarrow
If someone can't get a particular broadhead to fly well out a late model compound, they have one of the following concerns: An arrow with a spine that is too weak, a bow with the draw weight set too high for that arrow, an arrow that is not straight or it has inconsistant spine around it's circumference, not enough weight up front on the arrow, not enough drag on the rear end of the arrow, a bow where the center shot and/or nock height is incorrect, a torqued release or a bow where the cams are not timed.
No where will you find that speed will cause poor flight. It can only amplify another problem.