Rock River Arms Complete Mid A4 Upper .450 Bushmaster 16″ 5rd

The Rock River Arms Complete Mid A4 Upper is chambered in .450 Bushmaster and built on a mid-length A4 platform. It features a 16″ chrome moly barrel with a 1/24 twist rate and a lightweight 13″ M-LOK compatible free-float rail. This complete upper ships with a bolt carrier group, charging handle assembly and a 5-round magazine, and includes an RRA Operator Brake threaded 5/8-32.

Key Specifications

• The caliber is .450 Bushmaster.
• The barrel measures 16″ and is made of chrome moly with a 1/24 twist.
• The upper is a mid-length A4 configuration for balanced gas geometry on AR platforms.
• The handguard is a 13″ M-LOK compatible lightweight free-float rail.
• The muzzle device is an RRA Operator Brake with 5/8-32 threading.
• Included with the upper is a bolt carrier group and charging handle assembly.
• The package contains 1 magazine rated at 5 rounds.
• The finish is Anodized.
• The upper is designed to fit AR-15 lower receivers and is black in color.

This complete mid-length upper provides a ready-to-install option for shooters building or upgrading a .450 Bushmaster AR platform. Its combination of a chrome-moly 16″ barrel, 13″ free-float M-LOK rail, and included bolt carrier group and magazine make it practical for big-bore hunting and field use where a purpose-built, factory-configured upper is preferred.