Place the mount over the flange nut with the (2) 4-40 tapped holes toward the butt end. Line the 4-40 tapped holes in the mount up with the holes in the side of the receiver and put in the (2) 4-40 socket head screws.  It is very important that these holes line up to keep from damaging the threads when the screws are installed. DO NOT TIGHTEN! 

Move the nut around with a pin through the hole in the mount until the round part of the nut slips into the counterbore in the bottom of the mount. Put the 10-32 x ½”  flat head screw through the mount and into the nut. Tighten this screw and then the (2) 4-40 socket head screws. The 4-40 screws don’t need to be real tight! 

Put the 10-32 x ½ set screw down through the tapped hole in the top of the mount and tighten against the receiver. The purpose of the set screws is to keep pressure on the 4-40 socket head screws. Do not try to remove the 4-40 screws with the set screw tight!

You can also get some vertical adjustment with the set screw if you find your gun is shooting low & you don’t have enough adjustment with your scope. This can be done by loosening the 10-32 flat head screw & turning the set screw clockwise. For every ¼ turn of the 10-32 set screw you will move approximately 8” at 100 yards. Be careful if you do this as a small turn of this screw moves the vertical position quite a bit. Retighten the 10-32 flathead screw.