Not to hi-jack my own thread...but when building there is obviously a plethora of options...I think I've picked what lowers I want, but I don't know enuf about the uppers/barrels...who r some of the mid-level manufacturers that u have tried and trust to spend ur $$ on..for times sake let keep it to 300BLK AND 5.56...also since it will b my 1st build I think I want a full upper assembly..unless u can talk me into a complete build..remember I'm a novice