This is all you need to [Shred] grineer fighters into pieces in Railjack mode!

High fire rate and extended magazine, plus 100% status kills, literally, everything in just one clip, in less of a second. Perfect build, no need of anything else - extra damage doesn't help at all.

Only change I would possibly make is to add a riven with extra magazine and fire rate to make it even faster. But I believe either this gun or the mechanic of damage in Railjack are soon to be changed, hence investment into riven might not worth it in long term.