The Rock River Arms LAR-15M CLB Complete Upper in .458 SOCOM (brand part number SOC0820V1) pairs a forged A4 receiver with a 16-inch chrome moly bull barrel, giving the big-bore .458 SOCOM round a heavier, more rigid barrel profile than a standard-contour upper. At 16 inches, the barrel clears the federal rifle-length minimum, so no NFA paperwork is required. The muzzle is threaded 5/8×32 for RRA’s own Beast Brake, which ships installed and helps tame recoil on a cartridge built to hit hard at moderate range. A low-profile gas block sits under a 13-inch extended, lightweight aluminum free-float M-LOK handguard, and the upper ships complete with a bolt carrier group and charging handle assembly, finished in black.

Key Specifications

• Chambered in .458 SOCOM.
• Barrel length of 16 inches, clearing the federal rifle minimum.
• Features a bull barrel profile in chrome moly.
• Receiver is forged A4.
• Includes the RRA Beast Brake, threaded 5/8×32.
• Runs a low-profile gas block.
• Handguard is a 13-inch extended, lightweight free-float M-LOK aluminum rail.
• Includes a bolt carrier group and charging handle assembly.
• Finished in black.

Frequently Asked Questions

Does this include a lower receiver? No, this is a complete upper; it requires a compatible AR-pattern lower to build a complete rifle.

Is a 16-inch barrel legal without NFA paperwork? Yes, 16 inches clears the federal rifle minimum.

What comes included with this upper? The BCG and charging handle assembly.

Buy the Rock River Arms .458 SOCOM Complete Upper

Add serious big-bore power to your AR-pattern lower with a bull-barrel .458 SOCOM upper. Order this .458 SOCOM upper from Rock River Arms through our AR15 uppers lineup, and our Lubbock, Texas team will get your order ready to ship as soon as it’s available.