The MRE package is meant to do the job with M4 carbines, and accommodates a fixed A2 entrance sight tower with carbine duration gas process. It extends previous the front sight base, giving more rail Place for your mounting of tactical equipment. Includes a few KAC eleven Rib Rail Panels. https://garrettpcmyi.blogdemls.com/26333846/the-knights-armament-m4-quad-rail-diaries