Valence bonus: Magnetic

The Viral mods can be dropped for Critical Mutation and another mod of your choice if you use Nourish and/or have adequate Viral priming. [Accelerated Isotope], [Merciless Gunfight], [Anemic Agility], and [Galvanized Shot] are great options.

You can run [Critical Mutation] with Secondary Enervate, but you're better off using a different Arcane for that build.

[Galvanized Shot] doesn't do anything for the grenade, so [Hornet Strike] is an acceptable alternative. I wouldn't use [Galvanized Shot] if this isn't your main DPS weapon. If it is, the choice is up to you. [Galvanized Shot] can potentially deal a lot more damage with primary fire, but [Hornet Strike] provides consistent damage for both the primary fire and the grenade.

Use this with external fire rate and crit damage buffs if you can.