A fairly low Forma build that has great damage in auto and alt firing modes, played around about with different builds including [Hunter Munitions] and Status mods, this one works best for me, but do play around with what works best for you.

You can add a fourth forma if you feel that the recoil is too much which will let you add [Stabilizer], I feel like the recoil isn't too bad.

edit: after playing with the build in missions I've seen red crits doing up to 13mil viral damage.