Fail Zero AR-15 BCG Autopsy (Part 2)
This video details a critical defect found in a Fail Zero AR-15 Bolt Carrier Group (BCG) during maintenance. The instructor discovered undersized threads in the carrier, preventing screws from seating properly, and a crack caused by overtightening. The BCG was deemed irreparable and unusable due to these issues, highlighting potential problems with nickel boron coatings and manufacturing quality.










