Patrick,

Thanks for the tip. That has been on a to do list for a while now, but I never seem to get round tuit. I noticed that Tech-Sights sells Urathane inserts for the AR15 sight that reduce the aperture. Your method has got to be much less expensive and easier for sure but a factory solution may have some merit if they fit. http://www.tech-sights.com/inserts.htm

Dave