Swap out elements to taste. I guess viral/heat is where it's at, but I think electric looks cooler. [Carnis Mandible] would be a nice addition, but I don't have it so it's not there.

The idea is to build up a x2 combo, use the heavy attack, then back to guns.

If you're on a budget, rank 6 [Sacrificial Steel] gets guaranteed crits on heavy attack. [Pressure Point] is probably good enough in place of [Condition Overload]. Put in attack speed or range in place of [Bright Purity].