I'm not a QP by any means so if I'm out of line I apologize, but Samson also makes a front sight cut-out/pocket rail (STAR CXR
http://www.samson-mfg.com/ar-15_html.../STAR-CXR.html) and Midwest Indsturies makes one as well (MCTAR-20XG2
http://www.midwestindustriesinc.com/...ategory_ID=422).
Both require removal of the delta ring though.