The Geissele Super Modular Rail MK16 handguard, hammer forged barrel, and mid-length gas system work in concert for a package that delivers measurable increases in hit probability. Designed to take the full rigors of the new M855A1 (AB57) ammunition, the USASOC URGI also takes full advantage of its capabilities. Once the USASOC URGI is installed on an existing system, it essentially makes for a brand new weapon. The USASOC URGI is a near-clone of the upper receiver group currently in service with USASOC.