In the FWIW dept. I have a CETME, with iron sights my son shoots MOA groups at 100 yds. A friend bought a Socom 16 and added bells and whistles including a scope, bipod etc. He bought 6-7 different boxes of factory ammo to find out what it liked. None of the above, best was around 2 MOA, buckshot pattern. Thinking it might be him and not the gun he fired a few rounds thru my 6.5CM Howa and grouped sub moa. I've been wanting an AR-10 just for grins.