The Colt M4A1 is a "spray and pray" weapon, which is very similar to the ZM LR300 ML, but trades the rate of fire for more accuracy - which shifts its effectiveness to medium-sized open maps and against multiple exposed opponents. Its best shot in full auto. Although, unsilenced, it is one of the loudest guns in the game (with the exception of the SR8), the shooter may want to put laser pointer instead - to reduce automatic mode recoil even further.
