Canary's 'Ammo Regen Revolver' Specialist Shout
 Veteran Build - Warhammer 40k: Darktide 

A build created with the thought of an 'infinite ammo specialist build'. It's not quitttte that, given everything, but it's still pretty close. Using a revolver, you can more often than not get 1 shot 1 kill, and even in the instances where you don't you can usually make up the difference by the time you swap back to it. You'll still need to grab ammo here and there, but you can mostly just fly around with your extra stamina Duelling Sword and pick fights, while shouting and throwing frags to make space when you need it. 

Otherwise you just run around critting, stabbing, and getting free bullets back in your Revolver as you get kills. a full 10 will get you 2, otherwise you'll get 1. The idea is to not ever have to reload, but hard reloading when you can is good to do to just so you never truly run dry. Other than that, just keep activating Specialist for toughness and attack speed, and slash everything to ribbons.