Headshot isn't an insta-kill is it? There's multipliers like 1.1x..So if a gun dealt 30 damage, getting a headshot would deal 33 damage. So it would still take 4 shots to kill. If you mean 3 shots before any hit markers appearing then fair enough.
But generally speaking I agree with this game sometimes being terrible in the sense my bullets seem to be made of cheese.
You're right, the headshot multiplier for most guns from watching in depth from drift0r is 1.1x, and as he says, headshots at any range on 99% of guns are useless.
:/