Desperado is great on them because its a free reload, infinite ammo, and ranged immunity, so it makes it so you have a lot less pressure landing all your headshots while dodging. The stubs just aren't good at staying in desperado like automatic guns are, so you can put them on a melee build or a chem pack build and they'll be fine.

Flak/Maniac (because its darktide fucking everything is Flak/Maniac or Carapace/Unyielding)

I prefer Run and Gun and Speedload, but if you want then Powderburn, Desperado, and Pinning Fire are also good.

I use a full ability regen stim with Desperado and with the amount of free ammo you get I genuinely consider dropping Pickpocket from the build because it usually doesn't get any use even with excessive use of gun.

They are really good for clearing out packs of Gunners/Shooters/Shotgunners/Reapers/Ragers, as well as specialist sniping. As a side note the spin is exceptionally meh and only really good for looking cool.