Davidson Defense Cobblestone Prairie 10.5" 5.56 AR-15 Pistol Build Kit, M-Lok, w/ SB Tactical SBM4 Brace

Cobblestone Prairie 10.5" 5.56 AR-15 Pistol Build Kit, M-Lok, w/ SB Tactical SBM4 Brace

This is a complete AR-15 pistol build kit that gives you everything except the lower receiver to assemble a functional 5.56 NATO platform. The 10.5-inch barrel with carbine-length gas system cycles reliably in a compact package, and the SB Tactical SBM4 brace provides stable control without the length of a traditional rifle stock. All components are assembled and ready to install into your lower receiver.

Key Features

• 10.5-inch 4150 CrMoV barrel with 1:7 twist rate and phosphate finish
• 9-inch M-Lok handguard with 6061-T6 aluminum construction
• USA-made 5.56 NATO bolt carrier group with nitride finish
• SB Tactical SBM4 pistol stabilizing brace included
• Carbine-length gas tube with micro low-profile gas block
• Complete lower parts kit, buffer tube, buffer, recoil spring, and castle nut included
• M4 feed ramps and forward assist assembly
• AR-15 charging handle and ejection port door included

Perfect For

• Shooters building a compact 5.56 platform for home defense or range use
• Builders wanting a complete kit with minimal additional purchases
• Those seeking a maneuverable pistol-length AR with proven ergonomics
• Shooters who prefer the modularity of M-Lok accessory mounting

Compact 5.56 Pistol Platform

The 10.5-inch barrel paired with the carbine-length gas system creates a well-balanced short-range shooter. This configuration is popular for close-quarters applications where maneuverability matters. The barrel length keeps velocities reasonable for 5.56 NATO while the compact overall length makes it easy to handle in tight spaces. The phosphate finish on the barrel provides corrosion resistance for long-term reliability.

M-Lok Handguard and Accessory Compatibility

The 9-inch M-Lok handguard gives you multiple mounting points for lights, grips, and other tactical accessories without adding weight. The 6061-T6 aluminum construction keeps the upper assembly lightweight while maintaining rigidity. M-Lok slots run the full length of the handguard, so you can position accessories exactly where you need them.

SB Tactical SBM4 Stabilizing Brace

The included SBM4 brace is designed to stabilize the firearm when fired with one hand. The brace wraps around your arm and provides a consistent control point. This brace allows you to build a functional pistol platform without converting to a short-barreled rifle configuration. The brace is adjustable to fit different arm sizes and shooting preferences.

USA-Made Bolt Carrier Group and Domestic Components

The bolt carrier group is manufactured in the USA from 9310 alloy steel with a nitride finish for durability. The recoil spring and many other components are also USA-made, supporting domestic manufacturing. The combination of quality materials and proven design ensures reliable cycling across a wide range of ammunition types.

Lower receiver not included. BCG and charging handle are not included in the upper assembly only. Follow safe handling and manufacturer instructions. Ensure compliance with all applicable federal, state, and local laws.