Davidson Defense Backdrop w/Gauntlet Arms Brace 5-inch 1:10 9MM AR-9 M-Lok Pistol Full Build Kit

Backdrop 5-Inch 1:10 9mm AR-9 M-LOK Pistol Full Build Kit with Gauntlet Arms Brace

The Backdrop Full Build Kit is built around a 5-inch 9mm BC-9 direct blowback barrel with a Vertex Enhanced pistol-caliber billet upper receiver, a 4.2-inch tubular M-LOK handguard, a complete 9mm bolt carrier group, charging handle, and fixed polymer stabilizing brace. Lower receiver is not included.

Key Features

• 5-inch BC-9 barrel, slim profile, 1:10 twist, Parkerized finish
• Direct blowback operating system
• Vertex Enhanced pistol-caliber AR-15 billet upper receiver, black, integrated Picatinny top rail
• 4.2-inch tubular M-LOK aluminum handguard, black, 1.77" internal diameter, suppressor-ready
• KAK Industry 9mm Mini Compensator on 1/2x36 threads with 1/2-inch black crush washer
• 8620 alloy steel 9mm Nitride BCG, compatible with Glock and Colt pattern magazines, and mil-spec quality M4 charging handle included
• Complete mil-spec AR-15 Lower Parts Kit included
• Fixed polymer stabilizing brace included
• Lower receiver is not included.

Barrel and Operating System

The 5-inch BC-9 barrel is built in a slim profile with a Parkerized finish and a 1:10 twist suited to 9mm. This build runs a direct blowback operating system rather than a gas-driven cycle. The muzzle carries the KAK Industry 9mm Mini Compensator on 1/2x36 threads, secured with the included 1/2-inch black crush washer.

Upper Receiver and Handguard

The upper receiver is a billet aluminum unit built for the pistol-caliber AR-15 platform, finished in black with an integrated Picatinny top rail. It's paired with a 4.2-inch tubular M-LOK handguard machined from aluminum, finished in black, with a 1.77-inch internal diameter and a suppressor-ready design.

Bolt Carrier Group and Charging Handle

The included bolt carrier group is machined from 8620 alloy steel with a Nitride finish and an external extractor, built for compatibility with Glock and Colt pattern magazines. A mil-spec quality AR-15 M4 charging handle is included alongside it.

Lower Parts Kit and Buffer System

The kit includes a complete mil-spec AR-15 Lower Parts Kit with an A2-style pistol grip and full fire control group, along with the carbine castle nut and mil-spec receiver end plate. The buffer system cycles inside a fixed, heavy-duty AR-style pistol receiver extension.

Brace

A fixed polymer stabilizing brace in black is included, built in a lightweight, open-frame design with an integrated sling slot, mounted to the fixed pistol buffer tube used in this build.

Follow all manufacturer instructions and safe handling practices.

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