Davidson Defense Hyperion w/BTR Brace 10.5-inch Carbine-Gas 5.56 NATO AR-15 Drop-In Quad-Rail Handguard Pistol Full Build Kit

Hyperion w/BTR Brace 10.5-inch 5.56 NATO AR-15 Full Build Kit

The Hyperion w/BTR Brace is built around a 10.5-inch front sight base barrel chambered in 5.56 NATO, paired with a 7075-T6 aluminum upper receiver finished in black anodizing. It pairs a 7-inch M4 carbine-length drop-in quad-rail handguard, finished in black, with a six-prong steel muzzle brake and a fixed A2-style front sight base. A complete bolt carrier group, Mil-Spec charging handle, complete Lower Parts Kit, carbine buffer-system components, and a Magpul BTR pistol brace round out the rest of the build. The lower receiver is not included, leaving the buyer to select and supply that component separately.

Key Features

• 10.5-inch 5.56 NATO barrel with front sight base configuration
• Carbine-length gas system with stainless steel gas tube
• 7075-T6 aluminum upper receiver, black anodized finish
• 7-inch M4 carbine-length drop-in quad-rail handguard, Picatinny quad rail
• Fixed A2-style front sight base, USA-made steel components
• Six-prong steel muzzle brake, 5.56 NATO, black oxide and nitride finish
• Magpul BTR pistol brace included
• Complete Mil-Spec Lower Parts Kit and carbine buffer-system components included
• Lower receiver is not included.

Barrel and Gas System

The barrel runs 10.5 inches long, chambered in 5.56 NATO and built in a front sight base configuration rather than a low-profile gas block setup. Gas cycles back to the action through a carbine-length system, running a carbine-length stainless steel gas tube. This barrel length paired with a carbine-length gas system gives the build a shorter dwell time than a typical mid-length or rifle-length setup.

Front Sight Base and Upper Receiver

Mounted on the barrel is a fixed A2-style front sight base, fitted with USA-made steel components including the front sight post, plunger, and spring. The upper receiver is machined from 7075-T6 aluminum and finished in black anodizing, cut with M4 feed ramps for smooth feeding and fitted with a standard AR-15 forward assist assembly. The ejection port carries a standard .223/5.56 door with its rod and spring installed.

Handguard

The handguard is a 7-inch M4 carbine-length drop-in design finished in black, built around a Picatinny quad rail rather than a slimmer M-LOK profile. It mounts using a Colt AR-15 delta ring assembly, giving it the classic two-piece drop-in fit rather than a free-float clamp-on design.

Muzzle Device

Capping the muzzle is a six-prong steel muzzle brake chambered for 5.56 NATO and finished in black oxide and nitride. It threads onto the barrel's 1/2x28 pattern and is secured with the included 1/2-inch black crush washer.

Bolt Carrier Group and Charging Handle

A complete AR-15 bolt carrier group is included, made in the USA and listed for use across 5.56 NATO, .223 Remington, .300 Blackout, and .350 Legend. That broader listing describes the BCG itself; the barrel and chambering on this build remain 5.56 NATO. A Mil-Spec AR-15 M4 charging handle rounds out the upper's operating components.

Lower Parts Kit and Buffer System

A complete Mil-Spec AR-15 Lower Parts Kit covers the fire-control and lower-control internals needed once a lower receiver is on hand. Behind it sits a Mil-Spec heavy-duty six-position adjustable buffer tube, holding a standard AR-15 carbine buffer weighing 3 ounces and a standard USA-made recoil spring. A standard castle nut and Mil-Spec AR-15/M16 receiver end plate secure the buffer tube assembly to the lower.

Stabilizing Brace

Capping off the rear of the build is a Magpul BTR pistol brace finished in black. It's built for standard Mil-Spec carbine buffer tubes, matching the six-position buffer tube included with this kit.

Follow all manufacturer instructions and safe handling practices.

Ensure compliance with all applicable federal, state, and local laws.

Lower receiver is not included.