I heard you like Crits
and Bleed procs
and tentacles.

Swap out [Bladed Rounds] for [Hammer Shot] at higher difficulty.
Swap out Pax Charge for Residual Shock for more damage in higher difficulties.
Vigilant supplies is used only to get crit chance enhance procs.

If you can get a Riven, Swap out Primed Cryo Rounds or Bladed rounds but that would require another forma.
Looking for:

• Crit Chance
• Crit Damge
• Multishot

• Zoom/+Recoil
  We all saw this coming right?

I still think Cold damage is really nice on this just to get viral instead of crit damage but, its your call.

Unforma'd slot is meant to rotate mods out such as [Hammer Shot], [Bladed Rounds], [Sinister Reach], etc...