Rock River Arms 450 Bushmaster Mid-Length A4 Upper
Rock River Arms .450 Bushmaster upper receiver with 16-inch stainless steel barrel, mid-length gas system, free-float rail, and complete bolt carrier group assembly.
Rock River Arms .450 Bushmaster Upper Receiver
This complete upper receiver assembly delivers serious stopping power in a mid-length configuration suitable for modern sporting rifle builds.
Specifications
Caliber: .450 Bushmaster
Upper Receiver: Forged A4 configuration
Barrel: 16-inch stainless steel with 1:24 twist rate and cryogenic treatment for enhanced durability and consistency
Muzzle Device: Rock River Arms Operator Brake with 5/8-32 threading
Gas System: Mid-length with low-profile gas block
Handguard: 13-inch extended lightweight free-float rail with M-Lok compatibility for modern accessories
What's Included
- Bolt carrier group
- Charging handle assembly
- One 5-round magazine
Why This Upper Works
The .450 Bushmaster cartridge is purpose-built for hunting and defense applications where maximum energy transfer matters. The stainless steel barrel resists corrosion while maintaining accuracy, and the cryogenic treatment improves reliability. The free-float design eliminates barrel contact with the handguard, promoting consistent accuracy. The mid-length gas system strikes a balance between reliability and recoil management, making this upper suitable for both new builders and experienced shooters upgrading their arsenal.
