In 2014, American firearms designer Jim Sullivan offered a video clip job interview with regards to his contributions towards the M16 and M4 family members of rifles while Performing for Armalite. A famous critic on the M4, he illustrates the deficiencies present in the rifle in its present-day configuration. From https://ras-rail29517.blogdon.net/the-best-side-of-knights-armament-m4-quad-rail-45689040