Must have [Carrier] to solve the ammo problem with its weapon modded with the other 3 Vigilante Set mods to achieve a minimum of 20% chance for orange crits. (max of 30% if using the 2 Warframe Vigilante Set mods)

Must also have Arcane Tempo for more fire rate. (As of now, Arcane Acceleration only works on non-shotgun primaries)

Optional: Arcane Avenger, for +45% flat crit chance for more chance of orange crits. Can be paired with [Combat Discipline] Aura mod as the health loss is considered as damage. But then you'll need to have some form of healing to regain health. (Allies will also heal when they kill enemies)

I chose a base element of Toxin to combine with the Primed Electricity mod = Corrosive for its +75% damage on Hemocyte if its armor is completely stripped.

Alternatives:
[Galvanized Acceleration] :: [Fatal Acceleration]
[Primed Point Blank] :: [Point Blank]
[Galvanized Hell] :: [Hell's Chamber]
Shotgun Spazz :: Amalgam Shotgun Spazz
Critical Deceleration :: Blunderbuss
Primed Ravage :: Ravage
Primed Charged Shell :: Charged Shell
Frail Momentum :: Vigilante Fervor/[Vicious Spread]