All ranged were given bonus damage on all shots in 2.0, which is pretty much same as the “smiter” perk, only for ranged weaponry. So it’s actually 20% damage on 1st shot, same 20% damage on 2nd shot, and 40% damage on 3rd and consecutive shots, if all shots are quick enough for target to not leave stagger, and can stagger it in a first place. Even if a weapon incapable of inflicting stagger on targeted enemy at all — it will still have 20% damage bonus, but will not ever go to 40% unless someone put heavy stagger on target for you.
Here’s the quote from patch notes: