Evo 2: Crimson Overture: Increase Damage by +2 and On Kill: Increase Damage by +2 and +20% Ammo Efficiency for 5 seconds. Stacks up to 3x.
Evo 3: Rapid Reinforcement: +60% Reload Speed.
Evo 4: Commodore's Fortune: Increase Critical Chance by +6%.

Using this build with a frame that has Arcane Avenger will push it to just over 305% crit chance for guaranteed red crits. With its 18.2x crit damage multiplier on tier 1 (yellow) crits, we have a 52.6x crit damage multiplier on tier 3 (red) crits. Of course, this is all dependent on us ADSing which many people don't like doing. Add 2 green archon shards to your frame, grab your [Tysis] modded for Corrosive (innate), Magnetic, and Toxin (to stack Primary Blight), subsume Nourish onto your frame so you can add Viral to your [Tysis] and to this gun, prime the dentist, pull out this bad boy, and gun them down with the most satisfying display of red crits you will ever experience. If you don't wanna maintain Primary Blight, you can swap to Primary [Frostbite] and the [Epitaph] and spam it on everything which makes it easier to maintain. If that's ALSO out of the cards for you, Primary Deadhead will work just fine, but I would swap to [Xata]'s Whisper to double dip that headshot multiplier and swap Scope for [Primed Cryo Rounds] and [Hunter Munitions] for [Infected Clip] as you will be relying on raw damage pretty exclusively.

Riven can easily be replaced with [Vigilante Armaments].