in my experience, with the scope, its much easier to spray down 2-3 people with 1 mag with the aug than doing the complicated m4 spray pattern.
aug spray first 10-12 bullets is just down and slightly to the right and then hold for a second or so. you can kill 2-3 ppl with that. its actually almost the same angle as the first part of ak spray, you just have to delay going left after going down and to the right with your crosshair.
the sg is diagonally to the left and hold for a second, you can kill 2 ppl with that too.
if you spray without scope then these guns becomes very inaccurate very quickly, but i feel the same way about the m4a4. with the a4 even the second bullet seems completely random, sometimes it goes to the left of the enemy head, sometimes to the right, sometimes it goes over top. if i spray with m4a4 i usually try to pull down to center mass after getting the first headshot because of how random it is.
the m4a1 having less recoil and inaccuracy buildup doesnt have this issue as badly