Geissele URGi 14.5" Upper Receiver Group "near clone" from Potomac Armory - 2021 build

$1,369.95 - $1,669.99
Upper Receiver is made to order, and barrel is sent out for pin and weld, so anticipate a longer lead time. Pls consult Charlie's sales team for more accurate estimates when you order.

Geissele Upper Receiver Group, URG-I "near clone" built by Potomac Armory (2021-2022 vintage)


The US Army Special Operation Command is changing out the M4 upper receivers with this new improved model, which features the Geissele Mk16 DDC rail, and a 14.5" Government profile barrel and Surefire muzzle device

This model based off the original Geissele near clone correct upper.  Charlie's had worked closely with Geissele to bring this to market in 2018.  Now this is being built as issued by Potomac Armory.

Your choice of various Surefire muzzle devices will be installed and pinned and welded as ordered.

Each URGI is fitted with the handguard Geissele designed specifically for USASOC, the MK 16 M-LOK™ Super Modular Rail handguard with a full-length Picatinny top rail and lots of slots for other accessories. T-markings are engraved on the rail but not painted white to help keep the rifle unobtrusive.

Charlie's is working with Geissele and Potomac Armory to bring you a near clone version of the US Army's URGi upper replacement for the M4A1.   This is very much the same offering that Geissele produced in 2018, which was a commercial variant of the Army's URGi, an like Geissele's model in 2018, Potomac in 2021 is producing a build that is also extremely close.  The major difference between the clone and near-clone upper receiver groups has to do with the upper receiver, BCG and gas block.  The clone correct builds use Colt upper receivers and BCGs and NAVSEA styled Mk12 gas blocks.  The near clone builds by both Geissele and Potomac Armory use military grade contracted mil-spec upper receivers and military grade phophated and chrome lined BCGs, and use different gas blocks. 

Depending on availability, Potomac Armory will build this upper with one of the following barrels: Colt 14.5" Carbine Gas, Daniel Defense 14.5" Carbine or, or FN 14.5" Mid Gas. Currently, all barrels have been available.  If you have a preference, add a note to your order.  Colt carbine will be the default barrel.


  • Mil Spec M4 receiver hard coat anodized in black mil-spec 7075 aluminum with upper Picatinny rail T-marked engraved to match the Geissele Mk16, includes shell deflector & ejection port cover, contracted from tier-1 manufacturer by Potomac Armory
  • Geissele Mk16 Super Modular Handguard hardcoat mil-spec anodized in DDC with Geissele roll-marks and upper Picatinny rail T-marked engraved without painting to match the quality mil-spec upper receiver
  • mil spec Government profile 14.5" CMV 4150 steel barrel with 1-7" rifling & 1/2"-28 tpi muzzle threads, chrome lined and mil-spec phosphated exterior.
  • Geissele Airborne (military version with roll-marks) DDC charging handle
  • mils spec blackened steel low profile gas block with barrel dimpled set screws set with red Loctite.
  • Mil Spec M16 bolt and carrier group, contracted by a tier 1 manufacturer by Potomac Armory
  • Your choice of Surefire muzzle devices, pinned and welded in place by one of the best pin and weld shops in America (you might notice the weld)
  • Pinned and welded muzzle devices result in a barrel with an overall length of 16" or more, making the attachment of the upper receiver group to a lower receiver a "street legal" rifle and not a short barreled rifle, subject to the National Firearms Act.

Some may remember the original offering from Geissele in 2018 included a 30% off coupon from Surefire for both a SOCOM suppressor and a Surefire flashlight.  Those coupons have expired and are no longer offered.

What, you ask, is the difference between this URGI and the URGI that Geissele is producing for 2021?  Well, the first thing is that as of this editing in April, 2021, Geissele has not yet shipped any of the newer version of their URGI.  The next difference is that Geissele will not be using their own Geissele barrels in the 2021 URGI, and the upper receiver will be made by Geissele.  We are not certain which muzzle device(s) Geissele may choose to use when it starts to build their version of the near-clone URGi.  Geissele has changed muzzle devices in their Super Duty uppers on a few occasions.  Aside from that, the two are very similar.  Charlie's will be offering the Geissele URGi when is is produced, and we anticipate continuing to offer this near clone and the "clone correct" versions of the URGi in the future.

A note on barrels and gas blocks:  Barrels will be military grade Colt, FN or Daniel Defense barrels with M4 Government contour, and all will be identical with a 1:7 twist and 5.56 NATO chambering, chrome lining and made of 4150 Chrome Molly Vanadium steel, to military standards.  The supply of barrels is subject to change and if you are interested, you can ask our Charlie's sales team which barrel and gas block will be used during your build.  It is possible that you will have a choice.  The Colt barrels are carbine gas system, and a Sadlak long nose low profile gas block, constructed of steel and phosphate or nitride treated will be used on the Colt barrels.  Potomac is also sourcing Daniel Defense carbine gas system barrels and will use a PRI Mk12 gas block constructed of steel and a nitride finish.  While it is not initially anticipated, it is possible that we will have Daniel Defense mid-length barrels also available.  FN barrels with a mid-length gas system will be also used with similar Mk12 low profile gas block.  The gas blocks will be set with set screws and the barrels dimpled to hold the set screws in place and the screws will be held in place with red Loctite.  The Loctite adhesive is very strong, and is so strong, that we consider the installation to be semi-permanent, in that the gas blocks cannot be removed without destroying the gas block.  This is the same manner in which the military installs gas blocks on their USASOC URGI upper receivers, as well as on the Mk12 and Mk18 rifle systems.  It is very reliable.

A note on Surefire muzzle devices:  All of the Surefire muzzle devices will accept a Surefire SOCOM series suppressor, like the RC2 and Mini2. While the Warcomp will work with and fit the SOCOM suppressor series, the nature of the ports on the Warcomp may lead to less noise being suppressed, and higher back pressures in the suppressor, while not a problem, this does make the Warcomp more suitable for unsuppressed fire.  If you select WarComp, we time this as neutral (ports pointed up).  If you want it timed to the starboard side, please make sure to put that in the comments.  Both are correct.  Our gunsmiths prefer ports timed up.

To view the 2021 production URGI, click this link:  Geissele 2021 Production 14.5" URGI near clone 

To view the Clone Correct version, click this link:  Clone-Correct 14.5" USASOC URGi upper receiver group.

NFA Comment:  The 14.5" barrel is pinned and welded to make the barrel length compliant with the National Firearms Act, and is not a short barreled upper.  Removal of the pinned flash hider, or attaching a flash hider that is not pinned and welded will result in the upper being an NFA item, when attached to a lower receiver.

ITAR warning:  This item may only be purchased and shipped to US Persons within the USA.  This is a military item, which is restricted from export without US Government permission.