Not overpowered, but good. It is great for taking down adds, because a kill basically reloads the gun. Kill-kill-kill-kill just like that.
DO NOT ruin this weapon's PvE capabilities for the sake of your PvP.
-
This reminds me of a time in destiny 1 where shotguns got nerfed to the ground in PvP but in PvE, they got buffed by adding 300% damage! It was the ultimate boss shredder.