They have maximum damage of 33 (AFAIK) so it's ~33, ~66, ~99 (Death) I keep dying by the time I try to get to my third shot in, unless I am quite a distance away but most people tend to reposition when they take damage.
It's not a question of being OP, it's more of a question of what are they useful for? We already have Marksman Rifles, Assault rifles can do single and burst fire, so they can do quite a bit of damage at distance as well, if you know what you are doing. I just feel they don't really have a place in BF4 as they did in BF3. Maybe it's the shitty hitreg that's causing it, maybe I suck at using them, I will reserve further judgement once the new patch has been released.