Tested 3 different Versions of this Against 20x Grineer Bombard Steel path lvl 200 Eximus lineups.

My Old setup with Hunters Munitions & [Primed Shred] killed Equally Fast as Primary Crux setup, but it starts off extremely slow due to 0 merciless stacks & has to reload a bunch.
So we switch to Primary Crux & Heat.

[Primed Shred] does alot of Work here with heat & Primary Crux on. if u dont have [Primed Shred] u can go with [Rifle Elementalist] (Just barely behind in dps but less punch trough)
[Hellfire] Grants Heat a Higher Priority off the Status% & is most likely superior to [Thermite Rounds] for Raw dps & Status Heat Proc chance.
Right now its running purely off the 15% chance pr status application to get 300% crit. Its abit random, so Im not 100% sure how to boost this apart from actually modding crit or playing [Sevagoth] or [Ash]. Dps is still super good, but I feel there is some inconsistency with how often I crit without it.
Its Super broken on [Saryn] because her Toxin Lash & [Venom Dose] Mod application basically Double or Triple Dips the 15% chance to get 300% crit (red crits) so thats a way that works very well.
[Saryn] Also helps [Galvanized Aptitude] by up to 80% extra dmg with her toxin + corrosive added dps.

That Being said the Primary Crux Arcane Builds up the Arcane stacks faster than Merciless does & it isnt based off kills its based off weakpoint & headshot hits so it will also work on Bosses without downtime. (This is Far Superior than an arcane thats based off kills in terms of full power uptime)
Its also more fun to play with less reloads & more consistency.
If u play with Crux u will also GREATLY benefit from using a Primary Damage% scaling Frame or arcane like Arcane Rage or Roar / Eclipse Helminth.
If u really dont wanna play Faction mod, [Rifle Elementalist] will do the same thing pretty much.
& [Serration] & Spectral [Serration] or [Hammer Shot] & Possibly [Galvanized Crosshairs] is not Super far Behind, & works perfectly for ur daily low level Steel path missions.
Replace Hellfire with a Riven if u have a Heat + Status + Crit / Multishot riven for that slot.
Because this is kinda relying on heat stacks & we dont play [Serration] or Merciless arcane the single target Dps against Debuff capped enemies like Acolyte does feel abit low,
U can balance this by playing a frame like Saryn or with a chunky Roar + scaling around Galvanized Aptitude. Taking Advantage of Headshot multipliers also 4-5x multiplies the dmg, So keep that in mind if ur Struggling abit on those targets, Or just bring a chunky Secondary / melee with higher Raw Damage scaling.

This also Greatly Benefits from Primary Status chance Red Shards for Primary dps boost, as it will grant more 300% critical hits off Gotvas Passive skill. GO CRAZY:)
So if this really is ur favorite rifle I recommend picking 1 Frame to invest specifically for this setup with Primary Red Shards & some sort of % Damage scaling Skill or Subsume.

Hope you enjoy <3