Auric Helborer
 Veteran Build - Warhammer 40k: Darktide 

It's all about crits. If you crit you kill. 

Lucius Mk IV Helbore Lasgun has excellent crit breakpoints. Reciprocity , Surgical and the newly improved Deadshot guarantees crits. Tunnel Vision to mitigate Deadshots stamina drain. 

2 crit headshots to kill a Crusher. 

1 crit headshot to kill Reapers, Bulwarks, Maulers, Mutants and Plasma gunners. All other elites and specialists won't need crits to one-shot, as long as it's a weakpoint hit.

Pox Hounds die in 1 crit bodyshot. Mutants in 2.

With 6 stacks of Marksmans Focus the crits will one-shot all human gunners with bodyshots. The gun cleaves through more targets with Withering Fire , so it will kill several elites in one hit even when they're not all headshots.

Weight of Fire gives you flexibility. High rate of fire for when you need fully charged shots delivered quickly(most shots still crit), or hold for a split second longer to truly 100% guarantee crits. 

The MK IV doesn't need any additional damage blessings in Auric, as long as you crit.

Don't need Executioners Stance for these breakpoints, so I went with Voice of Command.

-One Motion is essential. Hold M2 and you'll be ADS almost instantly. You still have to charge the shot, so admittedly it's still slow.

-Desperado lets the bayonet one-shot all chaff(except Vanguards) if you hit the head. It's still not great, of course - quite slow. But it also helps your melee weapon, anyway.

-Ammo as the dumpstat on the Helbore. You could go with Stability, but I find I hardly ever spend any ammo because of Shock Trooper . I usually go entire missions without ever picking up ammo, or reloading mid combat.

-Close and Kill because it feels great with the Power Sword/Helbore combo. And we won't need the ammo from Survivalist . But when it comes to Aura, Blitz, Ability and melee weapon you can just go for whatever you prefer.