No drilling, tapping or major alteration. Guaranteed to hold zero. Can be removed and reinstalled easily. Replaces rear sight. Made in the USA of top grade military allan aircraft aluminum. Rings not included - accepts Weaver rings.

Remove the bolt, the rear sight and the spring loaded plunger found under the rear sight from rifle.

Place the base in location on the receiver of the gun with the (2) side holes to the rear. Line the 6-48 tapped holes in the mount up with the holes in the side of the receiver.  It is very important that these holes line up to keep from damaging the threads when the screws are installed. 

Pivot the mount downward to rest on the bridge while slipping the special wedge shaped nut, angle toward rear of receiver into its place. Thread the ¼-20 screw into the special nut but do not tighten. Do this carefully. 

When you have everything in place, tighten the two 6-48 screws in the rear & then tighten the ¼-20 socket head cap screw. If everything is seated correctly the bolt can be removed. Should the bolt catch on the special nut, try drilling the hole in the nut 1/64 larger. If this doesn’t work file or mill .005/.010 off the tapered part of the nut.