CMMG Receiver Extension and Stock Kit - Carbine, AR15 The CMMG Receiver Extension and Stock Kit is a comprehensive, ready-to-install solution designed specifically for AR-15 builders and enthusiasts. When combined with your choice of lower parts kit, this all-in-one carbine stock kit provides everything necessary to complete your lower group. Built from a combination of durable polymer and aluminum, the kit centers around a mil-spec 6-position receiver extension (buffer tube) and a fully adjustable M4-style buttstock, offering a customizable length of pull for a wide range of shooters. The sleek black matte finish integrates seamlessly with most AR-15 builds while providing long-lasting corrosion resistance. Product Highlights Complete Lower Group Solution: Includes a CMMG 6-position receiver extension, carbine buffer assembly, carbine action spring, and 6-position M4 buttstock assembly for a full, ready-to-install kit. Mil-Spec Buffer Tube: Features a mil-spec diameter receiver extension for broad compatibility with a wide range of aftermarket stocks and AR-15 components. 6-Position Adjustable Buttstock: Collapsible M4-style design allows shooters to fine-tune length of pull to match individual preference and shooting style. Quality Materials: Constructed from polymer and aluminum with a black matte finish, delivering reliable durability and a professional appearance. AR-15 Specific Fit: Engineered for the AR-15 platform, ensuring a precise, drop-in fit when paired with any standard lower parts kit. Specs Brand: CMMG MPN: CMM55CA634 UPC: 815835012629 Platform: AR-15 Material: Polymer/Aluminum Finish: Black Matte Buffer Tube Size: Mil-Spec Stock Positions: 6 Stock Type: Collapsible/Adjustable M4 Dimensions: 1.75" x 7.30" x 13.45" Weight: 1.75 lbs Kit Contents: CMMG 6-Position Receiver Extension, Carbine Buffer Assembly, Carbine Action Spring, 6-Position M4 Buttstock Assembly 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.