Hope I don't get in hot water but, there is a guy on "Accurate Shooter" selling some really nice grips for AR's with a thumb rest. I got one and the fit and feel are very good. Check him out. http://forum.accurateshooter.com/threads/my-new-ar15-rpr-match-tactical-grip.3982241/

$20 each
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HEY!!...You got my ammo??
# 10 G.I. Vietnam '66-'67