An Endgame Focused [Tigris] Build, This weapon has been sitting in my arsenal since it was meta, figured it needed a build to make it work in endgame. If viral isn't what your wanting, Swap [Vicious Spread] for Prime [Charged Shell], and mix elements for what you are currently fighting. Otherwise you can also swamp this out for a Prime Cleanse mod or take off the toxin mod and keep [Vicious Spread].
Arcanes: Primary Merciless, or Shotgun Vendetta, Shotgun Vendetta is better, only slightly depends on what you prefer or have.