MAKE SURE to hit "Apply Conditionals" and "Fire Mode Burst" for the REAL Stats! 171% STATUS AoE
With this build you get Viral/Corrosive/Heat for armor-melt and health damage. Since this build has over 171% Status and of course with Multi-Shot, each burst shot applies multiple guaranteed status procs.
You can swap out Vicious Spread with Primed Cleanse Grineer for even higher DPS, however, do not replace it with Blaze, you lose more DPS (Requires Additional Forma).
You can also swap out Toxic Barrage and/or Scattering Inferno with Contagious Spread and/or Incendiary Coat for more innate DPS, however, if you replace both you go down to 102.6% Status Chance (Requires Additional Forma).
Even without the Arcane Primary Merciless, you get 68k Burst DPS and 38k Sustained DPS.