Knight’s Armament URX3.1 556

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The KAC URX III Rail is a free floating, fully modular replacement forend for the AR-15 platform. Unlike traditional quad rail designs, the URX III incorporates short sections of M1913 Picatinny rail at its front end for mounting accessories, eliminating the commonly unused sections of rail for reduced overall weight and a more comfortable grip. A QD sling swivel socket is provided on each side at the rear of the rail for ambidextrous sling compatibility. Add-on KAC URX 3.1 Rail Panels and additional rail sections allow shooters to customize the forend to their needs (both sold separately).

Rifle Requirements: This URX III rail requires that the rifle have a pistol or carbine length gas system and a low profile gas block. It is compatible with mid length gas systems but will leave a small portion of gas tube exposed in this configuration. Disassembly of the rifle’s gas system and removal of the factory barrel nut will be necessary. This forend uses a proprietary barrel nut that MUST be installed using a KAC URX Barrel Nut Wrench (PN: 20495, Sold Separately). For AR-15/SR-15 based platforms only; not compatible with SR-25 variants. Installation instructions, barrel nut and hardware are included.

Additional information

Weight1.44 oz





3.1, URX






13.5", 8"


Knight's Armament


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