This is my index/railjack/whatever build. It strips armor with both the corrosive and heat proc, and can take down any single target. Unless I need crowd control or radiation specifically, this is the build.

IMHO [Heated Charge] is the 'swap out' mod on this build. If you need less damage and utility, swap it around for punch through, magazine capacity, or reload speed. If you want to cause heavy bleeds, swap for [Maim] (slash.) The build works fairly well without it, so I cater that slot to the targets when I need to.