I recently got Dawson Precision Rear fiber option sights. They are adjustable for windage and elevation. The windage adjustment works fine. The elevation has me baffled. If I turn the adjustment screw toward the "UP" arrow, it clicks but I don't see it moving. With further turns of the screw, it clicks some more then unscrews completely - meaning the screw comes out. Is there something wrong here? Or perhaps the elevation adjustment is just very subtle? Thanks for the help.