Galil is weaker but an easer gun to spray with than the AK. I personally like the AK and do single shots with it to the head because its a 1 hit kill but the other form is just short 2-3 shot bursts at the neck since recoil will pull the bullets up and into the head or you could pull down and try to keep all the bullets at the head area. I prefer using the AK though and if you know how to spray with it, it is good. I single shot long range, and spray short range.
The M4 is by far probably the best gun to spray with and the strongest one at doing so. It is also very accurate but it is weaker and does an 84dmg headshot if the person has a helmet. With this gun, i sometimes do single shot but only at very far ranges, at mid range-long rang i do a 2 shot burst to the head since it takes 2 shots to kill. At short, no matter what, i spray with this gun. It is so easy to get the bullets on target and spraying at the head is the easiest thing.
With all these guns though, you dont run and shoot as with almost every other gun except the SMG's. Strafe left and right