the intended trade-off for the low total ammo of this weapon is its fast firing ROF and higher base damage compared to other vanilla fast firing SMG.
Overkill do a little overhaul to weapon damage some time ago, and I havent got the time to go back to this mod and adjust the value accordingly.

@Alcat101 Y'know what. I take back what I've said. I found out that "Body Expertise" doesnt apply to Auto Pistols like the G18 or Dokkaebi's Smg. So i made a Pistol Crit build. Now Im shredding off the head of any Dozer dumb enough to waddle in my line of sight. Im doing more damage than any AR or Smg with Body Expertise Aced.

Well, considering it's in the pistol class, it's not exactly surprising that is has so little max ammo. If the damage is still that low, it might be a bit lackluster compared to most pistols, but it has decent DPS. Plus, its concealment really lends to it being a crit machine.