Pocket Brammas! This weapon does a LOT of damage and melts most enemies. Ice Storm actually does provide more sustained damage - With a higher magazine capacity, less time is spent reloading, which actually does affect DPS (and does increase your output significantly!)
The weapon throws several bombs at once. The alternative fire detonates these. Only four can be detonated at a time, but this build shoots out three to four in one go, so throw and immediately detonate after each shot in order to maximize your damage output.
I like to run this with a [Carrier Prime] to handle ammo. If you don't want to, swap the Exilus out. For more direct damage, swap out Hornet Strike for a Primed Bane mod.
Ice Storm is actually necessary for this build - Not only does it provide Viral damage, which is an extremely strong damage type, but the extra magazine capacity improves your burst and sustained DPS overall. Less reload time means more chucking out giant bombs.
You can swap [Primed Pistol Gambit] for [Creeping Bullseye], but it doesn't save a forma, and the latter choice lowers fire rate.