This is a quick no forma build incorporating the new [Damzav-Vati] mod. It works perfectly against infested and corpus and has a very good kill time on heavy gunners (unloading a full clip into a lvl 155 usually kills them).

You can use [Frostbite] instead of [Scorch], but it makes the one clip kill on heavy gunners inconsistent. You could always aim for the head in that case.

Planning to forma it up and trying out the impact dual stat instead of [Sure Shot], but considering you'd want corrosive to proc more than impact it probably won't improve the build.

Another potential improvement might be [Primed Heated Charge] instead of [Scorch].

As for rivens, status chance and other positives instead of Sure Shot. Ideally I'd imagine a + status chance, + multishot, + damage (could be elemental) and - max ammo (there are a few other ones that would be good, can't think of any right now).