I for one believe the need for suppressive fire means a belt-fed full calibre weapon at the squad level. Suppressive fire can only be provided by a proper machine gun. Unless a suppressive fire weapon can chew through bricks, concrete, wood etc it is a waste of space and weight. You shouldn't need to spray rounds on automatic, as heavy barrelled assault rifles are not heavy or robust to provide effective automatic fire. You should be only using 3-5 round bursts unless they are almsot on top of your position.