I've been able to get about 4" groups at 100m with Romanian surplus, and that's with a 5x Optic and a grip-pod. I'm not exactly Chris Kyle, so I think it's capable of more with a better shooter and/or ammo. As far as the lugs go, they look about the same as a normal AR bolt lugs, but honestly, without a micrometer or a 5.56 bolt to compare it to, I have no idea. I'd say emailing Windham would be your best bet there.
Got my Windham Weaponry Carbon Fiber in the mail today and I am really impressed with the fit and finish.
The lock up between the upper and lower is nice and snug. No movement at all. The balance is good; and for those who might be wondering like I was, the gas block rail seems to be the same height as the rail on the receiver.
The package came with the AR, a 10 round mag pinned at 5, a Plano style case and a generic sling. A steal for the price as far as I am concerned.
Time will tell how the carbon composite hold up but from the reviews I have read don't foresee any issues.
Thanks again Ryan and SFRC!!!