That RRA is pretty nice... but getting deals on them is kinda hard. To make her 'featureless' the flashhider is removable, and then you have to stick a comp on it, or a thread protector (no flash hider)
But if you like that, you may consider the below link, DPMS, muzzle crown will give better accuracy then threaded+accessory.
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=496810 I just ordered the 20" version yesterday and it looks like its gonna be a winner.
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=486925