If it was my decision, I'd suggest the slugshot take longer between shots. Like, maybe the pump takes longer, or it has a cooldown or something? That would make the slugshot much worse if an enemy is up close, but it would still work against distant enemies, especially if you can quickly get behind cover while it recharges.
(Also I like how it one-shots every hitscanner, so I wouldn't change that)
Still, it's up to you. I'm not the one programming this.
EDIT: OH WAIT YOU UPDATED IT AND I DIDN'T EVEN NOTICE.