A bare shaft should not fly that poorly.

You say you are getting good groups with field points.

How about broadheads?? That bow needs to be tweaked for good broadhead flight.

Macdaddy - I can group bare shafts very tight at 25 yds. - they fly perfectly straight if the bow is tuned for it.

A properly tuned bow will " usually" but bare shafts withen a few inches of fletched shafts at 20 yds.