Davidson Defense Warden Duty 18-inch Rifle-Gas 1:7.5 6MM ARC AR-15 Freefloat Keymod Handguard Rifle Complete Upper Build

Warden Duty 18 Inch 6MM ARC AR-15 Complete Upper with Rifle Gas and 15 Inch Keymod Handguard

18 inch 4150 CrMoV barrel in 6MM ARC with 1:7.5 twist rate, nitride finish, rifle length gas system, 15 inch freefloat Keymod handguard, 7075-T6 aluminum upper receiver with M4 feed ramps, nitride finished 9310 steel bolt carrier group, and charging handle. This complete upper delivers the velocity and accuracy potential of 6MM ARC in a precision oriented rifle length platform.

Key Features

• 18 inch 6MM ARC barrel made from 4150 CrMoV steel with government profile, nitride finish, and 1:7.5 twist rate optimized for heavier 6MM projectiles
• Rifle length gas system provides smoother cycling and reduced recoil impulse with the longer dwell time suited to 18 inch barrels
• 15 inch freefloat Keymod handguard made from aluminum allows accessory mounting without affecting barrel harmonics and covers most of the barrel length
• 7075-T6 aluminum upper receiver with M4 feed ramps and black anodized finish provides reliable feeding and corrosion resistance
• Nitride finished 9310 steel bolt carrier group delivers enhanced surface hardness and corrosion resistance compared to phosphate coatings
• 5/8x24 threaded muzzle compatible with suppressors and muzzle devices using 5/8x24 threads

Perfect For

• Precision oriented shooters wanting 6MM ARC ballistics with rifle length ergonomics
• Long range applications where the velocity advantage of an 18 inch barrel matters
• Hunters who need flat shooting trajectories and wind resistance with moderate recoil
• Builders looking for an accurate complete upper without the weight penalty of heavy barrel profiles

6MM ARC Optimized Barrel Configuration

The 18 inch barrel length extracts maximum velocity from 6MM ARC while maintaining reasonable overall length and handling. The 1:7.5 twist rate stabilizes heavier 6MM projectiles in the 103 to 108 grain range commonly used for long range shooting and hunting applications. The nitride finish hardens the bore surface and resists throat erosion, extending accuracy over thousands of rounds. The government profile balances weight distribution with stiffness, keeping the barrel light enough for extended shooting sessions while maintaining rigidity under the handguard. The .750 gas block journal provides compatibility with most adjustable gas blocks if you want to further tune the system for suppressed or unsuppressed use.

Rifle Length Gas System Advantage

The rifle length gas system uses the longest standard gas tube length on the AR-15 platform, positioning the gas port further down the barrel. This longer distance between the gas port and the chamber increases dwell time, the period when gas pressure is applied to the bolt carrier. The result is softer recoil impulse, smoother cycling, and reduced wear on internal components compared to mid length or carbine gas systems. With 6MM ARC delivering less gas volume than 5.56 NATO, the rifle length system ensures reliable cycling while keeping bolt carrier velocity controlled.

Nitride Bolt Carrier Group and Keymod Handguard

The 9310 steel bolt carrier group features nitride finish across all surfaces, providing superior corrosion resistance and lubricity compared to traditional phosphate or chrome finishes. The nitride process diffuses nitrogen into the steel surface, creating a hardened layer that resists wear and reduces friction. This means smoother cycling, easier cleaning, and longer component life. 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.

Follow safe handling and manufacturer instructions. Ensure compliance with all applicable laws. BCG and charging handle are included.