I purchased this to use on my 300 blackout upper and have since decided to go with a FDE receiver instead. It was used for mock up only, nothing more than finger tight with the barrel nut, zero rounds fired. The rear lug had a bur which I removed with some light filing as seen in the pics. I used some non-chlorinated brake cleaner to remove the anti-seize which is why the anodizing appears blotchy. $226.99 on DSG Arms, selling for $140 shipped.
Mocked up
Mocked up