Product Description The Radian Weapons Model 1 Complete Upper Receiver in 6mm ARC is a masterpiece of precision engineering designed for shooters who demand the absolute best. Built around an 18-inch barrel with a 1:7 twist rate, this complete upper is chambered in 6mm ARC and finished in a durable gray Cerakote coating. The design philosophy behind the Model 1 is straightforward: use the highest quality raw materials, the most precise CNC machining equipment, and the best components available to create a weapon that seamlessly blends form and function. Beyond quality and aesthetics, the Model 1 features fully ambidextrous controls, adding much-needed utility for both left and right-handed shooters. Every Model 1 is assembled by hand, one at a time, by a trained gunsmith who inspects, test fires, and cleans the weapon to personally guarantee it meets the most rigid quality standards. No detail has gone overlooked, which is why the Model 1, like every Radian product, is guaranteed for life. Product Highlights Sub-MOA Accuracy Guarantee with Black Hills Match Grade Ammunition for consistent and dependable precision performance Billet Machined 7075-T6 Upper Receiver with M4 Feed Ramps and a 17" proprietary aluminum M-LOK handguard featuring an integrated stainless steel anti-rotation pin 18" Barrel chambered in 6mm ARC with a 1:7 twist rate, Dead Air KeyMo Muzzle Brake, and 5/8x24 thread pitch Radian Raptor-SD Suppressor-Optimized Ambidextrous Charging Handle paired with an Enhanced Black Nitride M16 Bolt Carrier Group Rifle-length direct impingement gas system with a lightweight forward assist for smooth, reliable cycling in any condition Specs Brand: Radian Weapons MPN: R0905 UPC: 810098420976 Type: Complete Upper Receiver Caliber: 6mm ARC Barrel Length: 18" Twist Rate: 1:7 Thread Pitch: 5/8x24 Muzzle Device: Dead Air KeyMo Muzzle Brake Gas System: Rifle-Length Direct Impingement Handguard: 17" Proprietary Extended Aluminum with Magpul M-LOK Mounting System Charging Handle: Radian Raptor-SD Suppressor-Optimized Ambidextrous Bolt Carrier Group: Enhanced Black Nitride M16 Receiver Material: Billet 7075-T6 Aluminum Finish: Gray Cerakote Platform Fit: AR-15 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.