Daniel Defense DD new 10.3" Mk18 barrel kit

The Daniel Defense 10.3" Mk18 barrel kit — factory-take-off barrel, pinned low-profile gas block, gas tube, and DD RIS-II barrel nut in one bag, built for the Mk18 CQBR clone.

• Complete Mk18 barrel kit: 10.3" 5.56 NATO barrel, carbine-length gas tube, low-profile gas block, and DD RIS-II barrel nut
• Cold hammer forged at Daniel Defense's facility in Black Creek, Georgia
• Chambered 5.56 NATO, 1:7 twist — the clone-correct spec for a Mk18 CQBR
• Factory take-off: pulled from complete DD uppers so the gas block and gas tube ship already installed
• Rail-agnostic: runs under the DD RIS-II as delivered, or swap to a Geissele or other rail once the barrel nut comes off

The Mk18 CQBR is a Naval Surface Warfare Center Crane-developed 10.3" upper originally fielded to Naval Special Warfare and adopted across Special Operations for close-quarters work. A clone-correct Mk18 build depends on three things: a 10.3" 5.56 barrel with the correct carbine gas length, a pinned gas block, and a DD RIS-II rail mounted on the DD barrel nut. This kit bundles the first three so the builder can drop the barrel into a stripped upper, torque it with the included nut, and mount a RIS-II without sourcing individual parts.

Daniel Defense's cold hammer forging process uses opposing carbide hammers and a mandrel to shape the bore, chamber, and rifling in a single operation. The result is a bore with uniform grain structure, a chamber cut in the same pass as the rifling, and a service life that, in Daniel Defense's own published data, runs well beyond typical button-broached barrels. Every CHF barrel leaving Black Creek gets the same forging treatment, the same forged chamber, and the same high-pressure test regimen.

A note on the gas block: this is a take-off kit, so what ships is what was installed on the factory upper. Most of the time that is a generic DD low-profile block; occasionally Daniel Defense pins it through the barrel, other times it is a set-screw install; rarely a DD Mk12-style block comes through. If a specific gas block is required for a build, leave a note in the order comments and we will try to accommodate — a swap is possible but adds shop time. Unless the build is historical-significant, any gas block DD ships attached to a CHF barrel is going to run reliably.

The DD RIS-II barrel nut is the specific nut designed for the RIS-II rail system; it is the piece that makes the RIS-II mount correctly to the upper. Builders planning to run a different free-float rail can remove the nut along with the gas block and install the rail-specific hardware; for a clone-correct Mk18, the RIS-II is the program-spec answer and the nut stays.

Specifications

• Barrel length: 10.3"
• Caliber: 5.56x45 NATO
• Twist: 1:7
• Profile: Government / carbine
• Gas system: Carbine length
• Construction: Cold hammer forged, chrome lined
• Gas block: DD low-profile (pinned or set-screw; see note above)
• Barrel nut: DD RIS-II

This barrel kit is the clean foundation for a Mk18 clone — no guesswork on gas length, no mismatched small parts, no hunting for a correct barrel nut. We get these when we break down complete Daniel Defense uppers, which means inventory runs hot and cold; when we are out, expect lead time while the next batch of uppers comes in. Copy that — grab one while they are here, and pair it with a DD RIS-II rail for the program-correct finish.