to be used together with some form of armor strip for the hemocyte, anything that does the job works but personally i prefer a shattering impact vastilok (sarpa works as well)

Primed Heated Charge / Serration instead of riven is perfectly fine
exilus and arcane aren't really needed but they do help a lot

• arcane is basically nullified by damage reduction on the hemocyte, but still works wonders on the horde of infested - good for minmax but absolutely skippable
• [Steady Hands] is great to keep control of the weapon as it has some insane recoil, especially if you use arcane velocity (fire rate on crit), not strictly necessary but i heavily reccomend it

Update - [Primed Convulsion] in place of the riven would be even better than the other 2 options above, as it contributes to corrosive which does increased damage to the hemocyte and most infested