Davidson Defense Warden Duty 16-inch Carbine-Gas 1:8 .338 ARC AR-15 Freefloat Keymod Handguard Rifle Upper Build Kit

Warden Duty 16 Inch .338 ARC AR-15 Upper Build Kit with Carbine Gas and Micro Low Profile Gas Block

16 inch 4150 CMV steel barrel in .338 ARC with 1:8 twist rate, heavy barrel profile, parkerized finish, carbine length gas system, micro low profile gas block, 15 inch freefloat Keymod handguard, 7075-T6 aluminum upper receiver with M4 feed ramps, and GI birdcage flash hider. This upper build kit delivers big bore AR-15 performance with the stopping power of .338 caliber projectiles.

Key Features

• 16 inch .338 ARC barrel made from 4150 CMV steel with heavy barrel profile, parkerized finish, and 1:8 twist rate optimized for .338 caliber projectiles
• Carbine length gas system provides reliable cycling with the gas volume characteristics of .338 ARC in a 16 inch configuration
• Micro low profile gas block sits flush under the handguard with minimal height and weight, maintaining clean lines without protruding above the rail
• 15 inch freefloat Keymod handguard made from aluminum allows accessory mounting without affecting barrel harmonics
• 7075-T6 aluminum upper receiver with M4 feed ramps and anodized finish provides reliable feeding and corrosion resistance
• 5/8x24 threaded muzzle with GI birdcage flash hider compatible with .308 diameter suppressors and muzzle devices

Perfect For

• Hunters wanting AR-15 platform ergonomics with larger caliber stopping power
• Close to mid range applications where .338 diameter projectiles deliver superior energy transfer
• Shooters exploring big bore AR-15 cartridges beyond standard 5.56 NATO or .300 Blackout
• Builders looking for a specialty caliber upper that uses AR-15 magazines and lower receivers

.338 ARC Big Bore Performance

The .338 ARC cartridge delivers significantly larger projectile diameter and energy compared to standard AR-15 cartridges while maintaining compatibility with AR-15 magazines and lower receivers. The 1:8 twist rate stabilizes .338 caliber bullets across common hunting and defensive weight ranges. The heavy barrel profile provides additional rigidity and heat dissipation for sustained accuracy, particularly important with the increased pressure and heat generated by larger bore cartridges. The parkerized finish protects against corrosion and wear while providing a non-reflective surface. The 16 inch length balances velocity extraction with maneuverability, keeping overall length reasonable while maximizing the performance potential of .338 ARC.

Carbine Gas System with Micro Low Profile Gas Block

The carbine length gas system positions the gas port at the standard carbine distance from the chamber, tuned for the gas volume characteristics of .338 ARC in this barrel length. The micro low profile gas block minimizes height and weight compared to standard gas blocks, sitting flush under the handguard without creating a visible hump or adding unnecessary bulk to the front end. The .750 gas block journal provides compatibility with adjustable gas blocks if you want to fine tune gas flow for different ammunition types or suppressed use.

Keymod Handguard and Upper Receiver

The 15 inch freefloat Keymod handguard extends nearly to the muzzle and allows you to attach lights, grips, bipods, and other accessories using Keymod compatible mounts. The freefloat design means the handguard does not contact the barrel, eliminating pressure points that can shift point of impact as the barrel heats. The 7075-T6 aluminum upper receiver features M4 feed ramps machined into the barrel extension interface, improving feeding reliability with a wide range of bullet profiles and magazine types. The black anodized finish provides corrosion resistance and a clean appearance that matches the handguard.

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