Casual Kriegsman
 Veteran Build - Warhammer 40k: Darktide 

Goal of this build is to one-shot all human-sized enemies, balancing consistency with speed. If you can apply focus target to whatever you're aiming at, do so. The Mk V Helbore meets the necessary breakpoints for clean headshots, of course, as well as direct bodyshots, but you want the extra damage multiplier in case you hit a gunner's arm or something. You can and should fire into hordes to thin them out -- Withering Fire feels great there.

If the horde encroaches on your position, throw a shredder grenade underhand and clean them up with melee. If a lone poxwalker sneaks up and lands a jab on you, use your bayonet so that you always have either the +15% ranged damage from Kill Zone or the +25% ranged damage from Agile Engagement.

Technically, you don't need Exec. Stance for this build, but it's a very nice cushion if your team comes upon a wall of gunners for you to eliminate. Doesn't hurt for Maulers, either. For maximum survivability (sacrificing some thematic synergy), I recommend Infiltrate with Low Profile. VoC works but you should try to learn positioning well enough that you don't get surrounded by a particularly large horde.

I strongly recommend installing the "Extended Weapon Customization" mod to get a sight on the Helbore. Be mindful that the sight is slightly misaligned, so you need to aim a bit higher (bottom of the target circle) than you think for a clean headshot. The "Helbore Passive Charging" mod feels really nice too.

Since the patch hasn't dropped yet, I haven't tested this out yet (as it's modified from my current build on the live patch); if possible with the new iconic ranged damage passive, I'd like to modify the build to use the Chainsword instead (better stagger and more thematic vibes).