Davidson Defense Thumper 5-inch 1:16 45ACP AR-45 Freefloat M-Lok Handguard Pistol Upper Build Kit

Thumper 5-Inch 1:16 .45 ACP AR-45 Free-Float M-LOK Handguard Pistol Upper Build Kit

The Thumper Upper Build Kit is built around a 5-inch .45 ACP direct blowback barrel with a Vertex Enhanced pistol-caliber billet upper receiver and a 4.2-inch free-float tubular M-LOK handguard. Bolt assembly and charging handle are not included.

Key Features

• 5-inch .45 ACP barrel, slim profile, 4150 CrMoV steel, 1:16 twist, Parkerized finish
• Direct blowback operating system; gas tube and gas block not required
• Vertex Enhanced pistol-caliber AR-15 billet upper receiver, black, integrated Picatinny top rail
• 4.2-inch free-float tubular M-LOK aluminum handguard, black, 1.77" internal diameter, suppressor-ready profile
• AR-15 .45 ACP birdcage muzzle brake, Manganese Phosphate finish, on 37/64x28 threads with 5/8-inch black crush washer
• Bolt assembly and charging handle are not included.

Barrel and Operating System

The 5-inch .45 ACP barrel is machined from 4150 chrome moly vanadium steel in a slim profile with a Parkerized finish and a 1:16 twist. This build runs a direct blowback operating system rather than a gas-driven cycle, so a gas tube and gas block are not required. The muzzle carries an AR-15 .45 ACP birdcage muzzle brake finished in Manganese Phosphate on 37/64x28 threads, rated for .45 ACP, secured with the included 5/8-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 free-float tubular M-LOK handguard machined from aluminum, finished in black, with a 1.77-inch internal diameter and a suppressor-ready profile.

Follow all manufacturer instructions and safe handling practices.

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