Midwest Industries Enhanced Nitride Bolt Carrier Group BCG Black MI-BCG-556EH. Midwest Industries manufactured these Bolt Carrier Groups from strong 4130 steel for the body and add a nitrogen charge to the bolt to protect it from the damaging...
Midwest Industries Enhanced Nitride Bolt Carrier Group BCG Black MI-BCG-556EH. Midwest Industries manufactured these Bolt Carrier Groups from strong 4130 steel for the body and add a nitrogen charge to the bolt to protect it from the damaging...