Details
Warden Duty 18 Inch 6MM ARC AR-15 Upper Build Kit with Rifle Gas and Micro Low Profile Gas Block
18 inch 4150 CrMoV barrel in 6MM ARC with 1:7.5 twist rate, nitride finish, rifle length gas system, micro low profile gas block, 15 inch freefloat Keymod handguard, 7075-T6 aluminum upper receiver, and GI birdcage flash hider. This upper build kit delivers the velocity and accuracy potential of 6MM ARC in a precision oriented rifle length platform with a streamlined gas block design.
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
- 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 and covers most of the barrel length
- 7075-T6 aluminum upper receiver with black anodized finish provides corrosion resistance and structural strength
- 5/8x24 threaded muzzle with GI birdcage flash hider 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 who prefer the streamlined profile of micro low profile gas blocks under freefloat handguards
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 standard and adjustable gas blocks if you want to further tune the system for suppressed or unsuppressed use.
Rifle Length Gas System with Micro Low Profile Gas Block
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. 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.
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 lightweight aluminum construction keeps front end weight manageable while the Keymod system provides secure attachment points without covering the entire rail surface in unused Picatinny slots. The 7075-T6 aluminum upper receiver provides the structural foundation with black anodized finish for 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.
