The URGI Upper — short for Upper Receiver Group Improved — is the upper assembly specification developed by Geissele Automatics in response to SOCOM's requirement for a more durable, rail-forward platform over the legacy MK18 CQBR design. Where the original MK18 used the Daniel Defense RIS II rail on a 10.3-inch barrel, the URGI spec moves to the Geissele Super Modular Rail MK16 for a thinner profile, full free-float geometry, and improved heat management under sustained fire. The result is what SOPMOD Block II fielding units actually carry downrange — and what serious builders want on the bench.
At Charlie's Custom Clones, every URGI upper is built to the same specification the military contract demands. That means the correct Geissele MK16 M-LOK rail (not a look-alike), the proper cold-hammer-forged barrel in the correct contour, a carbine-length gas system on 10.3-inch builds, and a mid-length gas system on 14.5-inch configurations. No substitutions, no "close enough." If the clone is wrong, it's not a clone — it's a costume.
Our URGI upper clone offerings cover both primary service configurations: the URGI 10.3 upper used by CQB units running suppressed in tight environments, and the URGI 14.5 upper preferred for general-purpose carbine roles where the added velocity matters. Both ship as MK18 complete upper assemblies — bolt carrier group and charging handle included — so you can drop either onto any mil-spec lower and be function-ready without sourcing additional components.
If you are building an accurate SOPMOD Block II impression or you simply want the best-spec'd short-barrel upper available in clone-correct configuration, you are in the right place. Every upper on this page is inspected, documented, and shipped from our shop in the United States.