Caliber: 5.56x45mmEcommerce Platform: AR-15Muzzle Device: Flash HiderBarrel Length: 16Rail Length: 13.75Barrel Profile: V2 Button RifledBarrel Twist Rate: 1:7Barrel Material: SteelBarrel Finish: BlackMuzzle Thread: 1/2-28Receiver Material: Aircraft Grade AluminumHandguard Type: M-LOK RailGas System: Mid-LengthGas Block Type: Low ProfileFeaturesThe L89 upper receiver groups are engineered for peak performance, featuring a robust forged upper receiver, V2 button-rifled barrels, and the precision of our V2 4140 gas block for exceptional durability and reliability. These receivers come in a range of lengths and muzzle device configurations, allowing for complete customization to suit your specific needs. The L89 rail system is designed with 7-sided M-LOK compatibility, offering optimal attachment space for accessories and ensuring maximum versatility. Additionally, the integrated QD sling mounts enhance convenience and accessibility, making the L89 Upper Receiver Group a top-tier choice for those seeking unmatched performance and versatility in their firearm setup.