The patented CMR rail system is a lightweight, rugged, one piece, free float hand guard that when installed gives the upper a continuous 12 o'clock rail. The CMR system clamps to a proprietary barrel nut that can be installed on 5.56/.223 based AR platform systems. It was designed with the top 1913 rail for mounting the most common accessories, yet does away with the need for 1913 rail at the 3, 6, and 9 o'clock positions. Here other accessories can be directly mounted to it with a dedicated, simple, light-weight, mount. However it does allow for 1913 rail to be added, if needed, for some less common accessories. Additionally there are built in anti-rotation QD sling swivels in Mfg: Centurion Arms