Set the S&K mount over the rear sight so the screw holes in the front of the S&K mount line up with the horizontal hinge pin holes in the rifle. Align the rear hole in the top of the S&K mount up with the special nut. It is very important that these holes all line up to keep from damaging the threads when the screws are installed. Put the two 4-40 x 5/16th socket head screws through the hinge pin holes in the receiver & into the tapped side holes in the mount. Do not tighten at this time. 

Put the 10-32 x ¾” flat head screw through the hole in the top of the mount & into the special nut but do not tighten. Now tighten the 4-40 socket head screws - You don’t need to get the (2) 4-40 screws very tight! Now tighten the 10-32 flat head screw. Screw the 10-32 x ½” socket set screw into the top of the mount in the front hole, screw the 10-32 x 3/8” socket set screw in the rear hole and tighten both.  This will hold upward pressure on the mount, eliminating any movement in the mount & locking the 4-40 screws in place. Do not try to tighten or loosen the 4-40 screws with the 10-32 set screw tight as you will damage or break the 4-40 screws.