No issues, was using as a trainer but I'm slimming some things. Was a complete A posted BCM upper with 16" ELW BFH .625 barrel. I removed the A post and installed the 3 screw MI gas block and Gen 3 rail which is solid. BCG is BCM. Sights, covers and sling mount comes with it.

3-3k on the gun.
The BCG is BCM

No trades, upper 450 OBO in Chesapeake area