Product Description The Aero Precision Complete AR-15 Bolt Carrier Group (BCG) in 5.56x45mm NATO delivers Mil-Spec performance and long-lasting reliability for your AR-15 build. The M16-cut carrier body is machined from 8620 steel and finished in a Mil-Spec black phosphate coating, offering excellent corrosion resistance and durability under demanding conditions. The 5.56 bolt is machined from premium Carpenter 158 tool steel, shot peened for added strength, and individually High Pressure Tested (HPT) and Magnetic Particle Inspected (MPI) to ensure each unit meets rigorous quality standards. The properly staked gas key features a chrome-lined interior along with a chrome-lined firing pin channel for smooth and consistent cycling. A black o-ring insert on the extractor further enhances extraction reliability, making this a complete and dependable upgrade or replacement for any AR-15 platform. Product Highlights M16-cut carrier body machined from 8620 steel for superior strength and broad platform compatibility 5.56 bolt machined from Carpenter 158 tool steel, shot peened, and HPT/MPI tested and marked for verified reliability Mil-Spec black phosphate coating provides lasting corrosion resistance and a durable finish Properly staked gas key with chrome-lined gas key and firing pin channel ensures consistent, reliable cycling Black o-ring insert on the extractor for enhanced extraction performance and dependability Specs Brand: Aero Precision MPN: APRH100019 UPC: 815421020120 Caliber: 5.56x45mm NATO Finish: Black Phosphate Carrier Material: 8620 Steel Bolt Material: Carpenter 158 Tool Steel Carrier Cut: M16 Gas Key: Chrome Lined, Properly Staked Firing Pin Channel: Chrome Lined Extractor Insert: Black O-Ring Testing: HPT/MPI Tested and Marked Firearm Fit: AR-15 Disclaimer: We strive to provide accurate and up-to-date product descriptions, specifications, and images; however, errors or omissions may occasionally occur. We are not responsible for any inaccuracies or discrepancies in the content provided. If you notice anything incorrect or unclear, please contact us so we can correct it. When in doubt, we recommend verifying details directly with the product&';s manufacturer. ]]>