Davidson Defense Flopzoom .300 Blackout AR-15 Pistol Upper Build Kit M-Lok Handguard

Flopzoom .300 Blackout Pistol Upper

This is a complete upper assembly built on the AR-15 platform for .300 Blackout pistol configurations. The 7.5-inch 4150 CrMoV barrel features a 1:8 twist rate optimized for subsonic and supersonic ammunition, paired with a low-profile gas block and pistol-length gas tube. The 7075-T6 aluminum upper receiver is anodized for corrosion resistance, and the 7-inch M-LOK handguard provides a modern mounting solution for accessories.

Key Features

• 7.5-inch 4150 CrMoV barrel with phosphate finish and 1:8 twist rate
• Pistol-length gas system with low-profile gas block
• 7075-T6 aluminum upper receiver with anodized finish
• 7-inch M-LOK handguard in 6061-T6 aluminum
• 5/8x24 threaded muzzle for suppressors and muzzle devices
• HBAR profile barrel for accuracy and heat management

Perfect For

• Pistol builds using AR-15 lower receivers
• Suppressed .300 Blackout configurations
• Short-range tactical applications
• Shooters building compact, maneuverable platforms

Design Intent

This upper is purpose-built for .300 Blackout pistol platforms where barrel length and gas system tuning directly impact reliability and performance. The 7.5-inch barrel with pistol-length gas system creates a balanced platform for both subsonic and supersonic loads. The low-profile gas block minimizes sight line obstruction, and the M-LOK handguard offers modern accessory mounting without adding unnecessary bulk.

Suppressor Compatibility

The 5/8x24 threaded muzzle is standard for .300 Blackout suppressors and muzzle devices. Verify suppressor thread compatibility before mounting. The pistol-length gas system is tuned for this barrel length and will cycle reliably when properly configured with your lower receiver and buffer system.

Barrel and Gas System Details

The HBAR profile provides sustained accuracy during rapid fire while managing heat effectively. The 1:8 twist rate stabilizes a wide range of .300 Blackout projectiles from 110-grain to 220-grain loads. Pistol-length gas tuning means this upper requires a compatible lower receiver with appropriate buffer weight and spring configuration for reliable cycling.

Follow safe handling and manufacturer instructions. Ensure compliance with all applicable federal, state, and local laws. BCG and charging handle are not included. Verify suppressor compatibility before use. May. Dropship from. Davidson. Defense.