Anyone with a milling machine can open the 3/8" dovetail in the Ruger 1/4 rib for the NECG express sight. Jeffs Outfitters also offers a couple of express sights. One caveat: The Ruger 1/4 rib is glass hard and must be annealed before machining...just heat it up and bury it in sand to slowly cool. Hope this helps.

Otto