What sets the M4 RAS apart from other 2-piece quad rails out there is that it securely locks towards the rifle’s barrel nut via a clamp and screw arrangement, which makes it a very sound foundation upon which to mount tactical add-ons. Posted by BRAD on twenty third Jan 2020 https://knightsarmamentrail63604.blogdanica.com/29442730/the-greatest-guide-to-knights-armament-m4-rail