The Rock River Arms LAR-15M CLB is a complete, high-power 458 SOCOM upper assembly designed for the AR-Platform. It features a 16 chrome moly bull barrel with a black finish and a 1:14 twist rate for heavy projectile stabilization. Built on a forged A4 aluminum receiver, this unit includes a 13 lightweight free-float M-LOK handguard and a pre-installed RRA Beast Brake with a 5/8x32 thread pattern. This black anodized assembly comes fully equipped with a specialized 458 SOCOM bolt carrier group and charging handle, providing a plug-and-play solution for hunters and shooters seeking big-bore performance from a standard AR-15 lower. Note: The .458 SOCOM chambering is designed to function with standard AR-15 magazines and lower receivers, though specialized followers are often recommended for optimal feeding.