Oh, you need an actual game to anchor your weapons to? Limbus Company then, Pirate Gregor uses a flintlock with 7 bullets.
Though if you want to get to that high of a scaling(base crit dmg is only 115%) you need to work with his passive(unjust enrichment), then the support passive of LCCB Ryoshu(a lot of +% crit dmg on the final bullet), more support passives that add pierce dmg. Then ego gifts that enhance poise dmg. At that point his skill 3 just eradicates whatever's on the other side.
Tho, it's actually a pretty good game even if I say gacha is trash