Davidson Defense Aegis 8.5-inch Pistol-Gas 1:8 .300 BLK AR-15 Freefloat M-Lok Handguard Pistol Upper Build Kit

Aegis 8.5-inch Pistol-Gas .300 BLK AR-15 Upper Build Kit

This upper build kit delivers a compact, versatile .300 Blackout platform built on quality components. The 8.5-inch 4150 CrMoV barrel pairs with a freefloat M-Lok handguard and low-profile gas block designed for pistol-length cycling. The 7075-T6 aluminum upper receiver features M4 feed ramps and a forward assist assembly. This is an upper assembly only, so the bolt carrier group and charging handle are not included.

Key Features

• 8.5-inch 4150 CrMoV barrel with 1:9 twist rate and phosphate finish
• Freefloat 7-inch M-Lok handguard in 6061-T6 aluminum for accessory mounting
• Low-profile gas block sized for 0.75 inch barrel diameter
• 7075-T6 stripped upper receiver with M4 feed ramps and forward assist
• Pistol-length gas tube optimized for shorter barrel cycling
• AR-15/AR-10 5/8x24 GI birdcage flash hider with crush washer included
• Anodized black finish throughout

Perfect For

• Pistol-caliber AR builds in .300 Blackout
• Shooters seeking compact upper assemblies with quality freefloat handguards
• Builds prioritizing suppressor-ready platforms with shorter barrels
• Builders wanting modular, M-Lok compatible accessory ecosystems

Freefloat Handguard Design

The 7-inch M-Lok handguard floats independently from the barrel, eliminating contact that can affect shot grouping. This design supports consistent accuracy across different shooting conditions and ammunition types. The freefloat approach pairs well with the low-profile gas block, keeping the top rail clear for optic mounting. M-Lok slots run the full length for mounting lights, grips, and other tactical accessories without tools.

Pistol-Length Gas System

The pistol-length gas tube cycles the action using gas diverted from the barrel through the low-profile gas block. This shorter gas system is optimized for 8.5-inch barrels and reduces felt recoil compared to longer gas configurations. The Recoil Technologies Micro Low-Profile Gas Block maintains a compact profile while supporting reliable cycling with .300 Blackout ammunition.

Compact .300 Blackout Platform

The .300 Blackout cartridge delivers subsonic and supersonic options in a short-action package. The 1:9 twist rate stabilizes standard .300 BLK projectiles across both velocity ranges. The 8.5-inch barrel length keeps the overall package compact while maintaining velocity for effective range. The 5/8x24 muzzle thread pitch supports standard suppressors and muzzle devices designed for this caliber.

Upper Assembly Components

This kit includes the upper receiver, barrel, and handguard only. The bolt carrier group and charging handle are not included. These components must be purchased separately to complete the upper assembly. The stripped upper receiver accepts standard AR-15 bolt carrier groups and charging handles.

Follow safe handling and manufacturer instructions. Ensure compliance with all applicable federal, state, and local laws. BCG and charging handle are not included.