As you all know 1-2 punch shotguns pair really well with this build. Two melees to kill a barrier on GM level makes me nom nom on crayons hard. The best shotgun overall for this build is the ikelos shotgun with Turnabout. Turnabout gives a overshield on breaking shields. The origin trait also gives back ammo on breaking a shield. The overshield in combination with woven mail lets you tank quite a lot of extra damage. As far as i can tell this shotgun is the only one who can roll with turnabout and 1-2 punch, but the high ammo reserves makes it top choice if you want to go with a build like this. You can also pair it well with monte carlo (obviously) Thats all, happy hunting! Edit: forgot to mention that Turnabout also works on moth and dark legion adds. Quite a big deal, right?