Product DescriptionThe KAK Industry AR-15 bolt carrier group (BCG) is built for reliable cycling and long-term durability. It features a phosphate-coated carrier with chrome-lined internal surfaces to help protect against wear and corrosion under repeated firing. This BCG uses an M16 auto profile and includes a Carpenter 158 (C158) bolt for dependable performance in 5.56 platforms.Product Highlights Chrome-lined phosphate carrier for enhanced wear and corrosion resistance M16 auto profile bolt carrier group for AR-15 / 5.56 firearms Carpenter 158 (C158) bolt paired with a phosphate cam pin 4130 steel gas key for durability under high round counts Black phosphate finish for a proven, duty-ready exterior coatingSpecs Brand: KAK Industry Product Type: Bolt Carrier Group (BCG) Platform: AR-15 Caliber Compatibility: 5.56 Profile: M16 auto profile Finish/Coating: Phosphate (Black) Lining: Chrome lined Bolt Material: Carpenter 158 (C158) Carrier Construction: 8620 steel Cam Pin: Phosphate Gas Key: 4130 steel MPN: 425-3312-003 UPC: 811163035651Disclaimer: 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.