Product Description The HK MR762 A4 Upper Receiver Kit is a factory-built upper receiver and barrel assembly designed for the MR762/7.62 NATO platform. Built around HKs proven short-stroke piston operating system, it helps keep heat, carbon, and fouling out of the receiver for enhanced reliability and easier maintenance. This complete assembly features a 13-inch barrel with 5/8x24 muzzle threads, a free-floating handguard, and an adjustable gas block to better tune the rifle for different conditions and suppressor use. Product Highlights Factory HK MR762 A4 complete upper receiver and barrel assembly for 7.62x51 NATO /.308 Winchester platforms Short-stroke piston system helps reduce carbon and heat in the receiver for improved reliability 13-inch barrel with 5/8x24 threaded muzzle for common .30-caliber muzzle devices and suppressor mounts Adjustable gas block and free-float M-LOK handguard for performance and accessory flexibility Includes bolt group assembly plus HK proprietary buffer components; ships in an HK soft case Specs Brand: HK Model: MR762 A4 Upper Receiver Kit MPN: 51001919 UPC: 642230272545 Caliber: 7.62x51mm NATO / .308 Winchester Barrel Length: 13 in Muzzle Thread: 5/8x24 Operating System: Gas operated, short-stroke piston Gas Block: Adjustable Handguard: Free-float, M-LOK Finish/Color: Black (anodized) Included Components (as listed by sellers): Complete upper/barrel assembly, bolt group assembly, proprietary buffer, action spring, HK soft case 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 products manufacturer.