That's funny, I was in the CG at the same time as him training with a lot of the same people D7 LEDET, TACLET and IMLET and we NEVER trained with the M16 or M4 other than the standard range quals twice a year. Even the shorty M4's are too long and awkward when playing sneak and peek around a yacht, freighter or fishing boat. Chris has a lot of operational experience but not with a rifle unless they seriously changed TTP's after I got out.