Davidson Defense Reentry 4.5-inch 1:10 9MM AR-9 Freefloat M-Lok Handguard Pistol Complete Upper Build

Reentry 4.5-inch 1:10 9mm AR-9 M-Lok Pistol Complete Upper

The Reentry 4.5-inch 1:10 9mm AR-9 M-Lok Pistol Complete Upper from Davidson Defense is a complete upper for the AR-9 platform chambered in 9mm. The configuration includes a 4.5-inch medium-profile barrel, a 4-inch black aluminum slim-line M-Lok freefloat handguard with full top rail, a 7075-T6 anodized upper receiver with M4 feed ramps, a 9mm A2 birdcage flash hider, and a 9mm 8620 alloy steel bolt carrier group.

Key Features

• 4.5-inch 4150 CrMoV medium-profile barrel in 9mm with 1:10 twist rate
• Nitride barrel finish
• 1/2x36 muzzle thread pitch
• 9mm A2 birdcage flash hider, 1/2x36 TPI, phosphate finish
• 4-inch black aluminum slim-line M-Lok freefloat handguard with full top rail
• 7075-T6 anodized aluminum upper receiver with M4 feed ramps
• 9mm 8620 alloy steel bolt carrier group with nitride finish, compatible with Glock and Colt magazines

Perfect For

• Builders completing a compact 9mm AR-9 pistol configuration
• Shooters sourcing a complete upper with bolt carrier group included
• Builders prioritizing a slim-line M-Lok freefloat handguard with full top rail on the AR-9 platform
• Those seeking a 9mm complete upper with Glock and Colt magazine compatibility

Barrel and Handguard

The 4.5-inch barrel is chambered in 9mm and constructed from 4150 CrMoV steel with a medium profile and a 1:10 twist rate. The nitride finish covers the full barrel surface for corrosion and wear resistance. The muzzle is threaded 1/2x36 and includes a 9mm A2 birdcage flash hider with a phosphate finish. The 4-inch black aluminum slim-line M-Lok freefloat handguard features a full top Picatinny rail and provides M-Lok slot access along its length for accessory mounting. The AR-9 platform operates on blowback, with no gas system components in this configuration.

Upper Receiver and Bolt Carrier Group

The upper receiver is machined from 7075-T6 aluminum with an anodized finish and M4 feed ramp compatibility. The 9mm bolt carrier group is constructed from 8620 alloy steel with a nitride finish, features an external extractor, and is compatible with both Glock and Colt pattern magazines.

Follow safe handling and manufacturer instructions.

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