Zealot Gunman V2
 Zealot Build - Warhammer 40k: Darktide 

This is another build I've experienced success with in Auric Damnation missions. 

For the melee weapon, I choose the MK 9 Heavy Sword with Deathblow in order to cleave multiple enemies with the vanguard heavy attacks. You can easily chain headshots with the vanguard attacks of the MK 9, which causes Deathblow to proc easily. Headtaker is for additional damage, which is especially useful against bosses and beefier targets.

For the ranged weapon, I've been successful with the Graia Braced Krinkov with this build. You can potentially kill a horde poxwalker with a headshot if Fire Frenzy and Deathspitter are at max stacks with this gun. Also, the braced auto weapons, in general, are great against ranged opponents due to them causing ranged enemies to duck from suppression. Another reason why I'm choosing this gun over the Agripinaa and Columnus braced autos is due to the Graia having the most amount of ammo on tap compared to the two previously mentioned braced autoguns; you can pick up a mag and a half worth of ammo from a small ammo pickup. Did I also mention the Graia braced auto increases its fire rate when bracing?

For trinkets, I choose gunner and sniper resistance and extra toughness. The former two are for general damage reduction due to the sniper and reaper gunners dealing heavy damage if they shoot at you while you're unaware of them. Extra toughness means more toughness gained from Second Wind and The Voice of Terra. Zealot already has a good amount of stamina regen on tap. Feel free to swap one of these out for Bomber resistance so poxbusters deal less damage when they blow up near you.

For talents, this is built around Blazing Piety. The extra crit chance can be used by ranged weapons, which means the Graia braced auto gains extra lethality. Couple that with Duelist proccing, then you're dealing high amounts of damage against foes. Proccing Fury of the Faithful with Duelist active means armored targets get melted quickly. Also, extra toughness damage reduction from Enduring Faith, Benediction, and Good Balance means attacks against you deal ~30% of their full damage, assuming all three of these talents are active. Invocation of Death with the cleave of a MK 9 heavy sword = fast ability regen. Blades of Faith are effective against ranged elites and most specialists in game with headshots. To further solidify this gunman build for zealot, Dance of Death can let you play this game like a boomer shooter when it procs. 

This build is banger, assuming your teammates are close by and mindful of specialists closing in. Probably the main downside to this build is it may struggle against bosses if blazing piety is not up.