Wel,l I must be smarter then I thought.  I bought a stripped reciever and 5 30 round mags months ago.  I am building the weapon for my Grandsons birthday in Aug.  I got the lower parts from DD (daniel defense).  It will be in 5.56.  BTW I have never fooled with an AR, only shot 1 once.  When in the Navy in early 70's I trained on the M-14.  
So...which upper is in the middle of great or good.  I want him to have a 9" twist and a flat top.  
I do reload .223 for my Song Dog remover in 9" twist (Remington VTR).  AR's I am ill inform.  
Thoughts please for the upper?  
P.S. I bought this summer I bought 10 30 mags for him.  $13.00 a shot. 
Please pass you thoughts.
Jng