bcn complete lowerSeemed it around so often times and may't discover the blem. Everytime I feel I obtain one thing off, it is just oil smudges. Finest guess at this stage is scuffs on castle nut, or The 2 tiny silver spots within the flare in the magwell. 1mm dots at most. BCM QC will not mess all over It appears.The Mk2 higher receiver moves mass