First off, try lighter bullet. NEF rifle of all calibers usually shoot light bullets best. You can have a gunsmith check the head space but little can be done except to make sure there is the right amount of clearance when its closed. Also try a little shim of cardboard or plastic between the barrel and forend. Last but not least, go to the NEF forums at www.graybeardoutdoors.com. Lots NEF experts there.