| The half fishtail 5 m out from the bow could be that the lighting on the day allowed you to see the glinting from the second half of the oscillation. Perhaps the in first half the glinting was aimed away from you. It would seem strange for the movement to start 5m away from the bow. If it is a lighting thing, the first half of the oscillation would be away from the riser as if contacting something.
The cause could be the new fletchings, perhaps they need to be rotated a little to clear properly. It could be that as you tire you torque the bow a little causing the arrows to fly as described. |