I have seen this video. And I see what he is talking about. Anyhow, he is still shooting at bots on a shooting range. This gun has really low damage. And unless you have extremely good aim you won't be able to use it to its full potential.
Furthermore you just replied "no" to me, even though I just used your argument. You said the M4A1-S is not OP because of its slow fire rate and the damage it does. Well, the mp does even less damage. And at long range only 35 with a hs. I honestly have no idea how this is op at all. In a fight the rifles always have the advantage.