URG-I

URG-I

Caliber:　5.56 × 45mm M855A1

The full name of URG-I is "Upper Receiver Group, Improved". This project is a project initiated by the U.S. Marine Special Operations Command (USASOC) in 2017 to upgrade the existing SOPMOD II . Tender plan. The emergence of this project is partly because the handguard design with four-sided rails has become no longer popular in recent years (see my article "Picatinny Rails and Two Later Competitors" published on other platforms for details ). Some soldiers or units I will purchase other handguards to replace the handguards from Daniel Defense (DD), such as TORY 's ALPHA, or Geissele's SMR MK4, etc. Therefore, USASOC simply designated M-LOK as one of the requirements for upgrading. On the other hand, the M855A1 bullet equipped in recent years has a much higher chamber pressure than the original M855, which has caused the life of the original M4 to decrease rapidly. At the same time, the mid-length gas guide (Midlength, which refers to the position of moving the gas guide hole forward 2 inches on a barrel such as the M4) that has become popular in recent years has been proven to reduce the pressure of the gunpowder gas and extend the unlocking time, so it has improved reliability. , the overall life and accuracy have been improved, and when the floating handguard is installed, the triangular sight constellation and bayonet mount become redundant, so USASOC decided to purchase a medium-length gas guide device for this upgrade of the M4A1. As a result, several key requirements for URG-I have emerged: medium-length air guide, floating handguard, M-LOK interface, etc. After selection, the plan submitted by Geissele was finally selected in 2018.

The upper part is the traditional 14.5-inch M4 barrel. The length of the barrel behind the gas tube is 7 inches. The bottom part is the 14.5-inch medium-long gas tube. The length of the barrel behind the gas tube is 9 inches.

Predecessor of URG-I: Replacement of Geissele M-LOK interface SMR MK4 handguard on M4A1 US Army Special Forces soldier

URG-I does not purchase a new gun, but an upper receiver modification kit. It includes a standard M4/M4A1 upper receiver, equipped with Geissele's MK16 rail handguard. The top of the handguard is a Picatinny rail, left and right The sides and bottom are M-LOK interfaces, and the barrel is DD Company’s GOV barrel. The URG-I was originally set to have two models: long and short. The long barrel type is a 14.5-inch (368mm) barrel of M4 length, equipped with a medium-long gas guide; while the short-barrel type is not the 10.3-inch (262mm) of the Mk18. barrel, but the same 11.5-inch (292mm) barrel as the Colt Model 733 . Of course, the medium-length gas guide is only used for long barrels, because its gas guide hole is already in front of the muzzle of the short barrel. The choice of such a short barrel type is said to be because SOCOM once conducted a test and found that the performance of the 11.5-inch type equipped with a silencer at normal engagement distances is no different from that of the 14.5-inch type, which is far superior to the 10.3 in terms of accuracy and stopping effect. inch type, but the length is much shorter than the 14.5-inch type. However, after 2019, special forces seem to have accepted a small number of 10.3-inch URG-Is for use. In addition, the Air Force Special Operations Command (AFSOC) also received a small number of 10.3-inch URG-Is for use.

The basic parameters listed in the table below, and compared with the upper receiver kit of the original SOPMOD II system, it can be seen that the URG-I has been reduced in weight.

Although the project was initiated by USASOC, users include the Army's Special Operations Forces (Green Berets and Rangers, excluding Delta) and the Navy's Special Forces (mainly regular SEALs commonly known as White Seals, excluding Black Seals) DEVGRU), so the order is divided into the Army version (USASOC URG-I) and the Navy version (NSW URG-I), so there is a distinction in the NSN code. For example, the NSN code of the 14.5-inch USASOC URG-I is 1005-01-671-3911, while the NSW URG-I is 1005-01-671-3911; the NSN code of the 11.5-inch USASOC URG-I is 1005-01- 684-1906, while the NSW URG-I is 1005-01-671-3911. In addition, Geissele delivers accessories, which users receive and assemble themselves. The Army is assembled at Fort Bragg (originally named Fort Bragg, but due to the BLM Black Lives Matter movement in recent years, it was renamed Fort Liberty in June 2023) , while the Navy is as usual their ground weapons development center Crane ) assembly.

Geissele's MK16 rail handguard

In fact, the main components of the Army and Navy models are the same: the same DD barrel, Geissele handguard, SureFire 4-prong flash hider installed on the muzzle, and SureFire SOCOM silencer, and the charging handle is both from Geissele. The dark gold Airborne double-sided charging handle, the backup mechanical rear sight is from Matech, and the front sight is from KAC. The difference between the Army type and the Navy type is the number of M-LOK accessories it comes with: each set of the Army type is equipped with 3 Magpul 7-slot aluminum alloy guide rails and 1 set of Magpul QD M-LOK strap rings; while the Navy type is equipped with 2 A Magpul 7-slot aluminum alloy rail, a set of Magpul QD M-LOK strap rings, a Magpul tactical light rubber switch mounting plate, and 2 Geissele rail covers.

As for the Air Force type 10.3-inch URG-I, it is equipped with an OSS muffler.

The URG-I began to be equipped with the troops at the end of 2018 or 2019. Photos of the U.S. special forces using the URG-I began to appear around 2019 and gradually increased. However, there are also photos of the URG-I being used mixedly with the SOPMOD II equipped with a DD handguard. Discoveries are made from time to time.

Since the Geissele MK16 handguard does not have a detachable rail like the DD handguard, the M203 or M320 grenade launcher cannot be installed by hanging the barrel. However, in recent years, special forces have also become popular in using the M320 grenade launcher alone instead of hanging it on the gun, so it seems that the problem is not big. However, there are obviously still special forces who are eager for under-mounted grenade launchers combined with rifles, so it was not until 2023 that accessories for the URG-I under-mounted M320 finally appeared. However, since only one photo was exposed, it is not yet clear what it is. installation method.

The first exposed photo of URG-I installing M320 GLM should be a specially developed new installation accessory.

Various URG-Is in the gun library

This URGI M4 also uses MAGPUL’s D60 drum drum

On October 18, 2019, the M4A1 used by the U.S. Army's 3rd Special Forces Group in a joint tactical exercise participated in a joint tactical exercise at the Marine Corps Air Ground Combat Center (MCAGCC) training range in Palm City, California, has been replaced by the URG-I