Even if it's just arcane avanger any flat crit will turn the reload into an absolute monster (if it doesn't bug out and stop because you decided to slide) and get scaling crit per pulse which should be at least red by the last (maybe further with more buffs like [Harrow] and Adarza) also i recommend using the alt fire to spread some viral procs for even more damage
I try to make (relatively) good low forma builds that I personally use (or would if I had the forma/mods)