Product DescriptionThe Bushmaster QRC Complete Upper is a ready-to-install AR-15 upper assembly chambered in 5.56x45mm NATO and compatible with .223 Remington. Built around a 16-inch 4150 CMV barrel with a salt bath nitride finish, this upper is designed for durability, corrosion resistance, and dependable performance. It features a carbine-length gas system, a 1:7 twist rate for stabilizing a broad range of bullet weights, and a 7075 forged A4 flat top upper receiver with a black hard coat anodized finish. The free-float style M-LOK handguard offers modern accessory mounting flexibility, while the included salt bath nitride bolt carrier group, MPI tested bolt, and A2 birdcage flash hider complete this practical, duty-ready package.Product Highlights Complete Bushmaster QRC upper assembly for AR-15 platforms chambered in 5.56x45mm NATO and .223 Remington. 16-inch 4150 chrome moly vanadium barrel with salt bath nitride finish for long service life and corrosion resistance. 7075 forged A4 flat top upper receiver with black hard coat anodized finish for strength and optics-ready versatility. M-LOK handguard provides lightweight handling and flexible accessory attachment options. Includes salt bath nitride bolt carrier group, MPI tested bolt, carbine-length gas system, and A2 birdcage flash hider. Specs Brand: Bushmaster Model: QRC Series: Complete Upper Manufacturer Part Number: 0040017BLK UPC: 604206201324 Product Type: Complete Upper Firearm Fit: AR-15 Caliber: .223 Remington / 5.56x45mm NATO Barrel Length: 16 in Barrel Material: 4150 CMV Barrel Finish: Salt Bath Nitride / Black Nitride Twist Rate: 1:7 Thread Pattern: 1/2x28 Gas System: Carbine-Length Upper Receiver: 7075 Forged A4 Flat Top Receiver Material: Aluminum Receiver Finish: Black Hard Coat Anodized Handguard: M-LOK Handguard Finish: Black Bolt Carrier Group: Salt Bath Nitride Bolt: MPI Tested Muzzle Device: A2 Birdcage Flash Hider Color: Black 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.