You can swap Hellfire for Magnetic Capacity if you are fighting Thrax/Eximus units a lot.

Also, swap your Arcane to Primary Crux and your exilus slot to [Stabilizer] if you want less recoil and more status chance as shown below.

"Trumna is innate heat.
Viral / Mag / Heat - best general use element and uses Primed Cryo Round to maximise raw damage, viral has bonus against orokin, heat strips armor of orokin and grineer and viral status boosts damage to health on all factions. Magnetic is also good for Thrax/Eximus as magnetic status has bonus damage to overguard and causes a huge electric proc to occur once overguard breaks

Corrosive / Mag / Heat - can be good with nourish"

-- Ninjase