USED Tiger Rock AR-15 Bolt Carrier Group BCG Assembly Carpenter 158 Bolt Standard Design Black Nitride BCG-N. Specifications for Tiger Rock AR-15 Bolt Carrier Group (BCG) Assembly: Manufacturer: Tiger Rock Fabric/Material: Heat Treated Steel Carrier Material: 8620 Steel Caliber: 5.56x45mm NATO .223 Remington Gun Make: AR Platform Gun Model: M16 AR-15 Features of Tiger Rock AR-15 Bolt Carrier Group BCG Assembly: M16 Style (Full Auto) Mil-Spec Precision Machined 8620 Gas Carrier Package Contents: Tiger Rock AR-15 Bolt Carrier Group Assembly What firearm models does the manufacturer say Tiger Rock AR-15 Bolt Carrier Group (BCG) Assembly is compatible with? The manufacturer suggests that Tiger Rock AR-15 Bolt Carrier Group (BCG) Assembly is compatible with AR-15 M16Tiger Rock BCG-N: AR-15 Bolt Carrier Group Assembly Carpenter 158 Bolt Standard Design Black Nitride