最初设定的URG-I有一长一短两个型号，长枪管型是M4长度的14.5英寸（368mm）枪管，配中长导气装置；而短枪管型却不是 Mk18 的10.3英寸（262mm）型枪管，而是与 柯尔特733型 相同的11.5英寸（292mm）枪管。

This 14.5" Criterion will also outshoot a lot of other Mil-Spec rifles, and while it may not last as long, we can service our guns whenever we see an accuracy shift.

服役数量最多的是14.5英寸枪管版本的URG-I，已经基本在陆军特种部队和第75游骑兵团中代替了同长度Daniel Defense RIS II URG，10.3英寸版本换装较慢。 空军情况不明，但是已知至少有两个常规空军的救援中队和一个空军特种作战司令部的特种战术中队装备了URG-I。 三角洲部队从来没有装备过URG—I！ 题图：在美国海军陆战队Quantico基地武器训练营中接受测试的URG-I（中和右）和HK M27 IAR（左）自2018年，URG-I（上机匣组——改进型）就在美国陆军特种部 …

With the advent of the USASOC URGI, that quintessentially American silhouette has changed forever. The Geissele Super Modular Rail MK 16 handguard, hammer forged barrel, and mid-length gas system work in concert for a package that …

With the advent of the USASOC URGI, that quintessentially American silhouette has changed forever. The Geissele Super Modular Rail MK16 handguard, hammer forged barrel, and mid-length gas system work in concert for a package that …

21年8月9日 Geissele 14.5 URGI (Not Clone Correct) 这把urgi的第一期视频，也才初步组好，配置都属于是很经典了

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

The URG-I stripped upper increases the capability of the platform, with the inclusion of the Geissele Super Modular Rail MK 16 handguard, cold hammer forged, chrome-lined barrel, and bomb-proofed mid-length gas system.

The URG-I complete upper receiver includes a 14.5" GOV profile, Hammer Forged, ChromolyV, Chrome-lined barrel, with a 1:7" twist and includes a Surefire 4 Prong SF4P Flash Hider. The 14.5" URG-I uses a mid-length gas system and utilizes a Super Compact Gas Block with bomb-proof installation for reliability and optimal performance.