This gun is unironically extremely good. There's more than enough flex room to replace some mods for your preferences, but overall this thing can be a monster.

It can have the versatility of a crit/status assault rifle (with 300 rounds) and the stupid damage of the [Vectis Prime] with its secondary fire laser.

I had 0 difficulty using this gun on steel path, using both primary and secondary fire. They're both stupid good against all types of enemies.

For trash mobs, primary fire alone is usually enough to kill them outright. Use this to get your 3 stacks of deadhead and 5 stacks of Galvanized Scope (assuming you don't swap it out for critical delay / [Point Strike]).

For the tankier mobs, if you don't feel like holding down the trigger, get some status procs in with primary fire and then wipe the slate clean with the giant secondary-fire laser.

Feel free to use whichever arcane you like, personally I'll use deadhead or dexterity depending on if I'm using zenurik or not.

If you don't want to spend the extra forma for [Tactical Reload], don't. Be warned, it's sometimes faster to just swap to your secondary weapon for a second or two than it is to reload the entire thing, especially if you have a riven and it has negative reload speed (like mine does).

For flex mods, you can replace either [Galvanized Scope] or [Vile Acceleration] with [Point Strike] or [Critical Delay]. You could also replace it with a faction mod or [Thermite Rounds] if you want to proc more heat instead of viral.

If you have a riven, replace whichever flex mod it shares stats with (e.g. if your riven has fire rate, replace [Vile Acceleration], if it has crit damage, replace [Vital Sense]).

In case you are wondering about the lack of [Serration]:
Simply put, it's not worth the mod slot. If you don't know how damage is calculated in warframe, you get diminishing returns when you stack damage% mods ([Serration], [Heavy Caliber], etc) because they are not multiplicative to each other, but rather additive. When you combine the ~+400% damage you get through aptitude (5 different status procs, 80% damage each status type) and the +360% you get from a primary arcane, the extra +165% is a waste of a slot.