Indeed, the best build on Overframe for Fulmin.

Primed Fraction mod can be replaced with Serration (if you dont have primed fraction mod - dont use it) or [Galvanized Shot] if used together with an [Epitaph] or a [Nukor].

Why is there no virus in the status? Because this type of damage is bad and is only used as a debuff. If you remove the armor Grineer, then put the virus. Against Corpus Is A Toxin. Against Infest - Gas (Corrosion if Cambion Drift missions).

Falmin has a fairly low synergy, so if you take Riven Mod on it, then with ideal characteristics (Multi-shot, Critical damage, Damage and Minus). Otherwise, it makes little sense.

Yes, you will need scope to shoot in the head, but this should not be a problem in the PVE game.

Why isn't slash used? Because enemies will take longer to die.

You can change electro mod on [Galvanized Shot] or [Serration], if you want

have fun