Davidson Defense Spartacus 16.5-inch Mid-Gas 1:7 5.56 NATO AR-15 M-Lok Rifle Complete Upper Build

Spartacus 16.5-inch 5.56 NATO AR-15 Complete Upper

The Spartacus is built around a "Satellite" 16.5-inch 5.56 NATO medium-profile barrel, finished in QPQ nitride, paired with a 7075-T6 aluminum upper receiver finished in black anodizing. It pairs a 15-inch ultra-lightweight M-LOK free-float handguard, finished in black chrome, with an AR-15 A2 GI birdcage flash hider at the muzzle, running on a mid-length gas system. A complete bolt carrier group and Mil-Spec charging handle round out the upper, giving the buyer everything needed on the upper side.

Key Features

• "Satellite" 16.5-inch 5.56 NATO barrel, medium profile, QPQ nitride finish
• Mid-length gas system with micro low-profile steel gas block
• 7075-T6 aluminum upper receiver, black anodized finish
• 15-inch ultra-lightweight M-LOK free-float handguard, black chrome finish, monolithic top rail
• AR-15 A2 GI birdcage flash hider, 5.56 NATO/.223 Remington compatible
• Complete bolt carrier group and Mil-Spec charging handle included

Barrel and Gas System

The "Satellite" barrel runs 16.5 inches long, chambered in 5.56x45mm NATO and finished in QPQ nitride with a medium profile. Gas cycles back to the action through a mid-length system, running a stainless steel mid-length gas tube and a micro low-profile steel gas block sized to a .750-inch diameter.

Upper Receiver and Handguard

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 an AR-15 forward assist assembly. The ejection port carries a standard .223/5.56 door with its rod and spring installed. Over the barrel sits a 15-inch ultra-lightweight handguard finished in black chrome, free-floated and using an M-LOK attachment system with a monolithic top rail running along its length.

Muzzle Device

Capping the muzzle is an AR-15 A2 GI birdcage flash hider, compatible with both 5.56 NATO and .223 Remington. 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 upper remain 5.56 NATO. A Mil-Spec AR-15 M4 charging handle rounds out the upper's operating components.

Follow all manufacturer instructions and safe handling practices.

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