Product DescriptionThe Wilson Combat Bolt Carrier Assembly for 5.56 NATO is built by top domestic Mil-Spec contractors and is designed to deliver long-term reliability in AR-15 pattern rifles. The bolt is precision machined from Carpenter 158 steel, shot peened for increased strength, and includes a tool steel extractor and ejector with the proper extractor spring. Bolts are randomly batch HPT (High Pressure Tested) for added confidence. The 8620 steel carrier features a Parkerized exterior with an internally chrome-lined bore, plus a properly machined Mil-Spec gas key that is chrome lined, phosphated, and heat treated to GI specifications. The gas key is secured with Grade 8 fasteners and properly staked during final inspection for dependable gas system function.Product Highlights Mil-Spec 5.56 bolt carrier assembly ideal for spares, builds, and hard-use AR-15 rifles Carpenter 158 bolt, shot peened for strength, with randomly batch High Pressure Testing (HPT) Parkerized finish with internally chrome-lined carrier for durability and smoother cleaning Tool steel extractor/ejector; extractor made from 4140 gun-quality steel per Mil-Spec Chrome-lined, phosphated, heat-treated Mil-Spec gas key secured with Grade 8 fasteners and staked Specs Brand: Wilson Combat Manufacturer Part Number: TR-BCA UPC: 810025500719 Platform Fit: AR-15 / 5.56 case-head based AR rifles Caliber Compatibility: 5.56 NATO (drop-in fit for 5.56 case-head based AR rifles) Bolt Material: Carpenter 158 steel Carrier Material: 8620 steel Extractor Material: 4140 gun-quality steel (Mil-Spec) Finish: Parkerized Carrier Lining: Internally chrome lined Testing: Randomly batch High Pressure Tested (HPT) Gas Key: Mil-Spec; chrome lined, phosphated, heat treated; Grade 8 fasteners; properly staked 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.