Service rifle guys drill a 1/8" hole through the rear of the sight down into the receiver (while straight) but not into the elev knob. Then open the hole in the sight base to 5/32". Drive a long 1/8" dia roll pin into the base and let the sight slide up and down on the roll pin.
There are other ways, tapping and installing a stud but the RP is the easiest.
Last edited by Constructor; 03-06-2011 at 21:54..