This is an M10/11 build. The Heartbreakers/Moxxi weapons are key in this. You use an Amp shield with a Bloodletter to get perma amped shots. There should be 3 points in Big Surplus instead of Scorching RPMs but there is no Purple Tree.
The mechanics you can employ is to use a Rocketeer class mod, deploy IB, then swap to Bloodletter to keep the Amp shots whilst keeping IB out for the full duration of Rocketeer. If you feel like you want to sacrifice the IB damage and use Iron Cub, you can just swap to Bear Cub instead of double weapons and you don't need to swap class mods.
IB is just stronger and is also good for using Dakka Bear for safety and more damage against Bosses. Thanks for coming to my build talk!