Ive installed at least 10 MI hand guards on rifles. Everything from 6 in all the way up. Awesome price and high quality. I wouldn't put too much thought in a barrel on a carbine. Even the best barrel will shot about 3/4 @100 yards. Ive done a few Shilen and Kreiger and they are good but your limited with a semi auto. Too many moving parts. Spend the money on optics and trigger.

NRA LIfe Member, Colt, Sig, Smith & Wesson, Springfield Armorer, NYBIN , NYPD Firearms Examiner, Serial Number Restoration, Cerakote, Gunkote, and Duracoat finishes