This build is not the best, and does only do a better job then others with either a riven or firerate support via [Harrow] or [Wisp].
If possible try replacing the firerate, slash or primed damage mod (maybe also [Blaze] with a heat stat), with a riven mod that replaces said stat, while giving you an additional multishot and status chance.
Why?
Well 245 bullets with a multishot of 4+ and 300%+ status chance do a great job.

I honestly have a 116 Status chance, 99 fire rate and 140 multishot riven for this bad boy, while having -84% crit chance, and it still kills steel path with ease, without any Warframe ability to help with damage.
Kills nullifiers with speed, and only gets better with wisps speed buff, harrows 2nd or xatas whisper.

If you want a crit build go look up the [Kuva Kohm] since it is build for crits, while the normal one is build for status overload.