This Davidson Defense Lockdown upper build kit is engineered for performance and adaptability in .300 Blackout applications. Built around a 10.5-inch barrel with government profile crafted from 4150 Chrome Moly Vanadium steel with durable nitride coating and 1:8 twist rate, this kit offers optimized bullet stabilization across subsonic and supersonic loads. The pistol-length gas system with .750 gas block located under the handguard ensures reliable cycling. The upper receiver is constructed from lightweight yet robust 7075-T6 aluminum with anodized finish for corrosion resistance and features M4 feed ramps for reliable feeding and cycling. The carbine-length quad-rail handguard provides ample space for accessories and customization on all four sides. Topped with a GI birdcage flash hider with 5/8x24 thread pitch for versatility, this build kit is ideal for gunsmiths creating tailored firearms for various tactical applications or personal shooting preferences.
The 10.5-inch barrel features a government profile made of 4150 Chrome Moly Vanadium steel with a durable nitride coating for exceptional corrosion resistance and longevity. The government profile provides reliable strength while maintaining manageable weight for compact upper assemblies. The 1:8 twist rate offers optimized bullet stabilization for .300 Blackout ammunition across both subsonic loads (typically 190-220 grains) and supersonic loads (110-125 grains). This versatility makes the barrel equally capable for suppressed subsonic shooting with minimal sound signature and high-velocity supersonic applications for maximum energy delivery. The nitride finish extends barrel life and maintains performance even under demanding tactical applications.
The pistol-length gas system operates with a .750 gas block located under the handguard, ensuring reliable cycling with .300 Blackout ammunition across various loads and shooting conditions. This system is optimized specifically for the 10.5-inch barrel length, providing consistent performance whether you're running subsonic or supersonic ammunition. The .750 gas block dimension is standard for many AR-15 barrels, ensuring compatibility and reliable gas delivery for proper cycling. Note: The front sight post is not used as a gas block; the .750 gas block is located under the handguard.
The upper receiver is constructed from lightweight yet robust 7075-T6 aluminum with an anodized finish for corrosion resistance and long-term durability. The 7075-T6 alloy provides superior strength compared to standard 6061 aluminum, making it ideal for tactical applications where reliability matters. Equipped with M4 feed ramps, this upper ensures reliable feeding and cycling across various .300 Blackout magazines and ammunition types. The M4 feed ramps guide cartridges smoothly from magazine to chamber, reducing the potential for feeding malfunctions and enhancing overall system reliability.
The carbine-length quad-rail handguard provides ample space for accessories and customization on all four sides. Picatinny rails offer comprehensive mounting options for lights, lasers, foregrips, pressure switches, and other tactical gear exactly where you need them. This maximum mounting flexibility allows you to tailor the upper to your specific shooting preferences, whether for tactical applications, hunting, or recreational use. The quad-rail design accommodates multiple accessories simultaneously, enabling complete customization of your platform for diverse shooting scenarios.
The assembly includes a GI birdcage flash hider with 5/8x24 thread pitch, further enhancing versatility. The 5/8x24 threading is standard for .300 Blackout platforms, ensuring compatibility with a wide range of aftermarket muzzle devices including suppressors, compensators, and other flash hiders. The GI birdcage design provides effective flash suppression for improved visibility during shooting sequences while serving as a solid foundation for future muzzle device upgrades. This threading versatility allows you to adapt the upper to your evolving needs, whether adding a suppressor for subsonic shooting or upgrading to a more advanced muzzle brake.
Always follow safe handling and manufacturer instructions.
Ensure compliance with all applicable federal, state, and local laws.
Verify compatibility with your lower receiver before installation.
Caliber: .300 Blackout
Barrel Length: 10.5-inch
Barrel Material: 4150 CrMoV
Barrel Thread Pitch: 5/8x24
Barrel Finish: Nitride
Barrel Profile: Government, M4 Extension
Barrel Twist Rate: 1:8
Barrel Gas System Length: Pistol Length
Gas Block Size: 0.750
Gas Block: A2 F-Marked Base
Upper Receiver Material: 7075 T6 Aluminum
Upper Receiver Finish: Anodized
Upper Receiver: AR-15 Upper Receiver, M4 Feed ramps
Handguard Material: Aluminum
Handguard Color: Black
Handguard Style: Carbine-Length Quad-Rail
Muzzle Device: AR-15/AR-10 .308 5/8x24 TPI GI Birdcage Flash Hider
Muzzle Thread Pitch: 5/8x24
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