Before you mount your scope it can be zeroed by, placing the scope to it’s lowest magnification. Get a small mirror that is large enough to cover the obj. lens and sit the scope on this mirror. Looking through the scope you’ll see the cross hairs and dial it in so that you only see one set of cross hair. This will set the cross hairs to center of the scope and you’re good to go. Follow the directions lonewolf suggested to simplify setting the scope on the rifle to bore sight your set up. Good luck...