The NBS .223/5.56 Black Nitride Bolt Carrier Group was designed with strength in mind. Starting with a 9310 Steel Bolt, which is aircraft-grade material, this bolt has a high core strength rating, a high fatigue strength, and a high hardenability rating. 9310 steel, when treated properly, is about 7% better than Carpenter 158 steel, so you know that you will have a dependable BCG, when you drop this into your rifle.
This NBS BCG (Bolt Carrier Group) has been Nitrided, so that it can provide a long-lasting experience, and provide a significant upgrade to your AR-15. These BCG’s have also been Magnetic Particle Inspected and have been made to Mil-Spec Standards. It also has Mil-Spec 8740 Steel hard-chromed Firing Pins, Mil-Spec Gas Keys with Grade-8 screws that are staked and sealed with Permatex No.3, and they have shot-peened case-hardened D2 tool steel extractors. Plus, with the AR15Discounts satisfaction guarantee, you can buy your AR build components without apprehension. Our guarantee says if you are unhappy for any reason, you can send it back to us within 30 days for a full refund. No worries.
NOTE- The Salt Black Nitride BCG offers the dark, subdued finish that doesn’t change the specs of the Bolt Carrier, but it still makes the outside of the Bolt Carrier harder. This treatment increases the longevity of the part, makes it extremely wear resistant and durable, and this treatment protects the part from corrosion.
• Gas system: Direct Impingement
• Caliber: 5.56x45mm NATO/.223 Rem, .300 Blackout
• Finish: Salt Black Nitride
• Bolt: 9310 Alloy Steel (High Hardness)
• Carrier: 8620 Aircraft Grade Steel
• Extractor: Shot Peened and Case Hardened D2 Tool Steel
• Firing Pin: Mil-spec 8740 steel with hard chrome finish
• Gas Key: Mil-Spec w/ properly staked Grade-8 screws & Permatex No. 3 sealed
• Cam Pin: 8620 Steel w/ Black Nitride Finish
• Quality Control: MPI Inspected for QC