Builder’s Special 450 Bushmaster – Right Hand



Gas Block

SKU: UPR-BSRH-450 Category:


As of May 2024, allow 5-10 days for this item to be built and shipped.

Includes 6061 upper receiver (optional 7075 billet available), barrel, gas block, gas tube, and complete head-spaced bolt head.

Does not include hand guard, bolt carrier assy, charging handle, or muzzle device.

Barrel is installed and feed ramp is extended, blended and polished.  Barrel muzzle is threaded 11/16-24, 1:24 twist, 4150 chromoly steel.

Barrels available include a 16″ light weight and 18″ light weight.

Lightweight barrels use a .750″ gas block.

16″ uses a carbine length gas system, 18″ uses a mid-length gas system.

Barrel nut included is simply to hold the assembly together and is thrown away after user installs their own hand guard.  Nut may be Blemished.

Also available with optional Superlative Arms Adjustable Gas Block.

Allow 5-10 days to ship.