Because of what Greg said and the hit registeration timer doesn't really affect them due to their firing speed: for example if a bar user and a pbp user stood and spammed into eachother the pbp user would win since many of the bars shots wouldn't register. Also shotguns should just be used for their spread not insane damage kind of like the blunderbuss or sawed shotgun. Basicially with stacked damage it's either OP or underpowered there doesn't seem to be a middle ground.