In 2014, American firearms designer Jim Sullivan delivered a video job interview about his contributions towards the M16 and M4 relatives of rifles while Doing the job for Armalite. A mentioned critic on the M4, he illustrates the deficiencies present in the rifle in its present configuration. From the video, https://judahboykr.dbblog.net/2775725/the-fact-about-kac-drop-in-rail-that-no-one-is-suggesting