Product Description The TacFire SS-RK556 Unassembled Rifle Build Kit is designed for AR-platform builders who want a comprehensive parts package to complete a rifle build (lower receiver not included). This kit features a 16" 5.56 NATO M4-contour barrel with a durable nitride finish, paired with a 15" M-LOK free-float handguard for lightweight strength and accessory versatility. Included components also cover essential upper and buffer system parts such as a stripped billet upper receiver with M4 feed ramps, charging handle, dust cover, forward assist, and a buffer tube assembly with spring and 3 oz buffer. A USA-made lower parts kit and an A2-style black pistol grip round out the build-ready package. Product Highlights Complete AR-platform unassembled rifle build kit (lower receiver not included) for streamlined rifle assembly 16" 5.56 NATO M4-contour barrel with nitride finish for durability and corrosion resistance 15" M-LOK free-float handguard provides a rigid, lightweight mounting platform Includes stripped billet upper receiver with M4 feed ramps plus charging handle, dust cover, and forward assist Buffer tube kit components included: aluminum buffer tube, spring, 3 oz buffer, end plate, and castle nut Specs Brand: TacFire Manufacturer Part Number: SSRK556LPK UPC: 745559515239 Platform: AR Platform Caliber: .223 Rem / 5.56x45mm NATO Barrel Length: 16" Muzzle Thread Pattern: 1/2"-28 TPI Handguard: 15" M-LOK free-float Upper Receiver: Stripped billet upper receiver with M4 feed ramps Included Muzzle Device: Birdcage flash hider with crush washer Grip: A2-style black pistol grip Includes: USA-made lower parts kit; charging handle (aluminum with steel latch); dust cover; forward assist; receiver end plate; castle nut; aluminum buffer tube; 3 oz buffer; buffer spring 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.