Davidson Defense Gythium 16-inch 1:10 9mm AR-9 Freefloat M-Lok Handguard Rifle Upper Build Kit

Gythium 16-Inch 9mm AR-9 Upper Build Kit

The Gythium upper build kit delivers a complete upper assembly for 9mm AR-9 builds with a 416R stainless steel barrel, free float M-LOK handguard, and 7075-T6 aluminum receiver. This kit includes everything needed for the upper receiver assembly except the bolt carrier group and charging handle.

Key Features

• 416R stainless steel barrel with 1:10 twist rate optimized for 9mm projectiles
• Free float M-LOK handguard for accessory mounting and rail flexibility
• 7075-T6 aluminum upper receiver with M4 feed ramps and black anodized finish
• 9mm A2 birdcage flash hider with 1/2x36 thread pitch
• AR-15 forward assist assembly and ejection port door assembly included
• Direct blowback operating system for reliable cycling

Perfect For

• Builders looking for a complete upper assembly solution without BCG and charging handle
• 9mm AR-9 platform builds on a budget
• Shooters wanting reliable 9mm performance in the AR platform
• Customization projects using existing lower receivers

Design Intent

The Gythium platform prioritizes reliability and value in the 9mm AR-9 space. The 416R stainless steel barrel resists corrosion from frequent 9mm shooting, while the 1:10 twist rate stabilizes standard and subsonic 9mm projectiles effectively. The free float design isolates the barrel from handguard contact, maintaining consistent shot placement across different shooting conditions.

M-LOK Accessory Ecosystem

The 15-inch M-LOK handguard integrates with a wide range of modern tactical accessories including lights, lasers, and grips. The free float design means accessories mounted to the handguard won't affect barrel harmonics or accuracy. M-LOK slots run the full length of the guard for flexible positioning.

Build Compatibility

This upper assembly fits standard AR-15 lower receivers configured for 9mm. The direct blowback system requires a lower receiver and bolt carrier group specifically designed for 9mm blowback operation. The 1/2x36 thread pitch on the muzzle device accommodates standard 9mm suppressors and muzzle devices with matching thread specifications.

Receiver and Finish Quality

The 7075-T6 aluminum upper receiver offers excellent durability and weight efficiency. The black anodized finish resists corrosion and provides a professional appearance. M4 feed ramps ensure reliable feeding with standard 9mm magazines and ammunition types.

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