I have an 11.5" CMMG chrome lined medium profile barrel with 1:7" rifling, 5.56 Nato chamber. The parkerizing is nice and uniform and the front sight base is forged and properly pinned in place. The muzzle threads are made correctly with a final pass and seem well made. As far as chrome lining goes, the bore and chamber look good to go. The crowning is well made too.
I have shot about 4000 rounds through this one without problems. I haven't benched this setup for real accuracy tests, but from prone unsuppored position with an Aimpoint M2 and surplus ammo I can put 20 rounds into a 6" group at 150 meters every time. That's about 3.5 MOA, which is by no means an indication of superb accuracy, but goes a long way to prove consistency. The typical five shot groups have been around 1.5 MOA or so at the same distance.
Those figures may not look that impressive compared to many other results that you see posted on this forum, but this rifle is not meant for shooting groups and I shoot it unsupported. However, I have no doubts that this barrel could very well shoot MOA from prone supported position with an ACOG. Heck, I think I'll give it a go next week just for kicks.
For what it's worth, my friend has a CMMG 16" mid-length barrel in his recce carbine, and it is easily a sub-MOA barrel.