ATI is beefy but not heavy: http://www.atigunstocks.com/ar15-forends/89-ar-15-aluminum-8-sided-15-free-float-forend.html
It has mount holes at 45° angles around the circumference of the forend so you can mount stuff where it should be w/o expensive offset mounts.
I also had it Cerakoted (Sniper Grey) because I din'd like the factory finish. It's never beenand never mounted -- to fat for my dainty hands. :) 130 bucks!
Amram@techie.com