The M8 was ungodly before it was nerfed. No gun should have that much damage combined with an insane RoF and no recoil.
There is still plenty of reason to use it over the SWAT due to its faster burst cycles, which makes it much more attractive without Selective Fire than the SWAT, which is pretty much gimped without it.
Russian is my first language, so yes there may be a spelling error or two. I <3 Jesus.