The LWRC REPR MKII 7.62mm NATO 16.1" 1:10" 5/8x24 Spiral Fluted Barrel Patriot Brown CA Compliant Complete Upper Receiver is a high-performance firearm component designed for precision and compliance. This complete upper receiver is chambered in 7.62mm NATO, a cartridge renowned for its versatility and reliability. The 16.1-inch spiral-fluted barrel with a 1:10 twist rate ensures optimal bullet stabilization, while the 5/8x24 threaded muzzle allows for easy attachment of muzzle devices. Finished in Patriot Brown, this upper receiver is California compliant, featuring a fixed magazine and other state-specific modifications. The LWRC REPR MKII upper receiver is built with a monoforge design, integrating the rail base for enhanced durability and rigidity. It also includes LWRC's patented short-stroke gas piston system, which offers superior reliability and reduced maintenance compared to traditional direct impingement systems. This upper receiver is perfect for shooters seeking a high-performance, compliant option for their AR-10 style lower receivers.