You could replace shotgun spazz with a primed faction mod, though I think ideally you wanna keep viral on there. Though this should get you some pretty decent dps right here as is.

After some testing, changed the exilus slot out for [Vigilante Supplies]. As you might guess, this build rips through ammo. If you have good recoil control this will [Shred] most enemies you put in front of it. If you get the fire rate boost from [Wisp] you'll be dumping the [Mag] faster than light.

Edit, I swapped out Shotgun Spazz for Amalgam Shotgun Spazz as I figured the loss in +5% fire rate is an acceptable/minimal loss in dps to trade for a +45% revive speed which will help if you need to revive a team mate in a high stress situation. If you'd prefer normal shotgun spazz, or simply don't have the amalgam version, go ahead and swap it out for the normal version.

Edit: (Post Galvanized Mods) Still have to do some testing with [Galvanized Savvy], however, this config should get you the most burst DPS out there. Middle click and jump to them and left click and they die. Nothing more to it. You will be dumping your magazine quickly as before, but as long as you control the recoil, you should be shredding enemies no problem. What's life without a little bit of fun? [Vigilante Armaments] will be the most likely to go to make room for [Galvanized Savvy]. Considering this isn't really a crit build, those enhanced crits will be very few and far in between especially if you're not running a [Smeeta Kavat] that can enhance your crit chance. Who can pass up a [Condition Overload] on a shotgun with a boat load of status effects?