Shotgun Marksman
 Veteran Build - Warhammer 40k: Darktide 

• This build allows for you to absorb some punishment (not quite to gold toughness standards but above average), knock out elites/specialists/shooters, have decent ammo economy, and create some space for yourself and your teammates through staggers. Through toughness regen/damage resistance from Confirmed Kill , Exhilarating Takedown, and Out for Blood combined with Executioner's Stance's passive 10% toughness regen allows you to stay in the fight. In addition, the weapon choices will let you create space when you're starting to become overwhelmed by hordes.  The focus is to headshot as many enemies to keep your Marksman's Focusstacks up (doesn't take much with the shotgun), and be the designated marksman to take down priority specials, elites, gunners, and shooters. This build is a fantastic anti-gunner build so your team won't get shredded. The ammo economy is *okay* at best, but your people will be thankful a room full of gunners will be gone faster than a fart in the wind.
• Taking advantage of the Agripinaa Mk VII Combat Shotgun tight spread in ADS makes it a fantastic weapon to score headshots with. The headshot hitbox is marginally higher than your sights are, so adjust accordingly. When you start understanding that, headshots are actually easier to do and maintain than almost any other single-shot ranged weapon in the Veteran's arsenal. In addition, the alt fire slug will stagger both crushers and bulwarks instantly.  Bulwark menacingly walking towards you? Slug shot from the shotgun followed up by two shots to the head. Crusher? Slug shot then finish them with your shock maul. Rager? Put a slug to instantly headshot them or stagger them. 
• Munitorum Mk III Shock Maul is my preferred weapon. Between the easy stagger to trigger Skullcrusher (including the alt fire stun) and High Voltage being activated any time you hit an enemy, you're going to be doing solid damage overall. For hordes, do Heavy Attack > Light Attack (repeated). For single target, Alt Fire Stun > Heavy Attack (repeated).
• When using this build, are you going to stagger enemies as much as an Artibrator? No, but it does the job while being able to do consistent ranged damage and horde clear. Would Voice of Command be viable for this? 100%, but you won't get those 1 shot breakpoints on some targets with your shotgun. And let's be real, activating Executioner's Stance when you open a door and the whole room lights up yellow, you can pump 2 rounds down range at head height and you'll instantly have all stacks for Marksman's Focus. It's pure dopamine.
• Fun fact about the Marksman's Focus : you can stay on your current stacks if you get any headshot with a melee weapon, so you won't lose stacks just by switching to melee. This whole build centers around weakpoint hits and will keep them up in the meantime.
• You can go with either Shredder Frag Grenade or Krak Grenade . I prefer Shredders due to the pure CC offered by them. In addition, shredders will stagger enormous groups of enemies of all types allowing you to proc your blessings that rely on stagger for your weapons. The only downside to Shredders is that you might struggle a bit with armor. That’s what Kraks are for. When using Kraks, choose Grenadier instead of Grenade Tinkerer so you can deal with walls of armor.

Mind you, I'm not the best player (seen from the video below), but I feel like this build is viable if you're able to work with all its moving parts