Yes, you need the offset insert kit to adjust them. But if you have the turn in type front mount and the rear mount with the screws on each side, just adjust the screws to get the left right thing centered up. First, take the scope off, place it front side up against a mirror and look into the scope, you will see two sets of cross hairs, adjust the screws until they are on top of each other and the scope is set to zero adjustment. Then do the bore sighting thing with the windage adjustable rings, then fine tune it with the scope adjustments. Larry