Geissele Mk16 rail for 11.5" Mk18 CQBR 10.5" DDC

The Geissele Mk16 rail in 10.5" DDC is the program-correct handguard for a URG-I Mk18 Mod 3 CQBR clone — the rail currently fielded on the Army's 11.5" Upper Receiver Group, Improved, Close Quarter Battle configuration.

• Program-correct for Mk18 Mod 3 URG-I (CQBR) clones — the rail on the current-issue 11.5" URG-I CQBR
• 10.5" M-LOK octagonal profile in DDC, Type 3 hard-anodized
• Upper-receiver alignment tabs — the Mk16's key evolution over the Mk14, locking rail-to-upper index
• NSN-marked or Geissele P/N marked — we receive both
• Fits 11.5" and 12.5" carbine-gas barrels

The Mk naming — why this rail has two numbers

This handguard is the Mk16 rail in 10.5", built for the Mk18 weapons system with an 11.5" barrel. The Army designates the upper the Close Quarter Battle Receiver, Upper Receiver Group Improved — URG-I — and the current variant is the Mk18 Mod 3. The rail is the Mk16 because that is Geissele's current-generation Super Modular Rail for the URG-I program.

The Mk16 is the latest evolution of the Super Modular Rail line, derived from the Mk14 but adding upper-receiver tabs that lock alignment between the rail and the upper. That alignment feature is what the US military required for the URG-I program. The Mk16 is slimmer in both diameter and overall height than the Mk14, with an updated proven-pattern Geissele barrel nut for easier installation and higher rigidity.

M-LOK runs the full octagonal perimeter for accessory flexibility. The DDC color matches the issue URG-I furniture.

What's in the package

• Mk16 rail, 10.5" DDC
• Geissele barrel nut
• Allen wrench for the smaller tab screws
• All rail screws and back-end tab

Not included: larger Allen wrench for the barrel nut screws, barrel nut wrench, gas block.

Notes on current production

Geissele is now shipping these rails with 17-4 stainless grommets (unfinished) for the sling QD cups. Product photos on older listings may show the prior configuration without grommets — current shipments include them. The upper rail is T-engraved to meet the mil-spec requirement, with no paint in the T-marks, and the Geissele brand is roll-marked on the rail. Each rail ships with either an NSN or a Geissele commercial part number.

Manufacturer's P/N: 05-650S

 ITAR warning: This item may only be purchased and shipped to US Persons within the USA. This is a controlled military item, restricted from export without US State Department authorization.

The Mk18 Mod 3 URG-I is one of the cleanest clone targets in the catalog, and the Mk16 rail is the single part that defines the build. Copy that — grab one while they're here.