Luth-AR Complete Rifle Kit, 16-inch Fluted Bull Barrel, Fixed Stock

The Luth-AR Rifle Kit (brand part no. RKB161) bundles nearly everything needed to build a complete AR-15 rifle around a 16-inch fluted bull barrel, short of the stripped lower receiver itself, which builders source separately. The kit centers on a fully assembled 16-inch fluted bull barrel upper machined from 416 stainless steel, paired with a 15-inch KeyMod palm handguard, a 1:9 right-hand twist across 6 lands and grooves, an M4 feed ramp, and a button-broached bore. The barrel is threaded 1/2×28 and paired with a .936 gas block and a rifle-length gas tube, and the upper ships with a fully assembled bolt carrier and an A2 flash hider already installed. Builders choose between an MBA-1 fixed rifle buttstock or an MBA-3 adjustable carbine buttstock assembly, and the kit includes a complete .223/5.56 lower parts kit to finish out the lower’s internals. It’s built for AR-15 builders who want the added rigidity and heat capacity of a bull-profile barrel without sourcing and matching each individual component themselves.

Key Specifications

• Chambered in .223 Remington.
• Barrel measures 16 inches with a fluted bull profile.
• Machined from 416 stainless steel with a button-broached bore.
• Rifling uses a 1:9 right-hand twist across 6 lands and grooves.
• Threaded 1/2×28 and paired with a .936 gas block and rifle-length gas tube.
• Includes a fully assembled bolt carrier and A2 flash hider.
• Ships with a 15-inch KeyMod palm handguard.
• Includes a complete .223/5.56 lower parts kit.
• Buyer’s choice of an MBA-1 fixed or MBA-3 adjustable buttstock assembly.

Frequently Asked Questions

Does this kit include the stripped lower receiver? No, builders need to source a Mil-Spec stripped lower receiver separately; everything else needed to complete the build is included.

What’s the benefit of a fluted bull barrel? A bull profile adds rigidity and heat capacity for sustained accuracy, while fluting removes some of that added weight without sacrificing stiffness.

Is the upper pre-assembled? Yes, the 16-inch fluted bull barrel upper ships fully assembled, including the bolt carrier and flash hider.

Buy the Luth-AR Complete Rifle Kit, 16-inch Fluted Bull Barrel, Fixed Stock

Build a complete AR-15 around a rigid, pre-assembled bull-barrel upper. Order it through our Luth-AR lineup of AR15 build kits from our Lubbock, Texas gun shop.