Helbore Vet
 Veteran Build - Warhammer 40k: Darktide 

From top to bottom:

Ranged damage is your friend. As much as possible.

Shredders for horde control. If you get jumped, drop a shredder to stun everything, and start pushing with your shovel. You'll quickly get out of the horde. Your job is elite hunting, and you have carapace on your helbore. With full stacks of marksman's focus you can one shot them on the slowest charging helbore. You don't need kraks on this build.

Elite damage and crit on first 20% ammo means most of the time you're critting, so you don't even need to reload. Grenades from ammo packs is a godsend if your team keeps leaving you alone and you have to use them more regularly than normal. Especially common on lower difficulties.

Survivalist for ammo. Demolition stockpile because your grenades get you out of melee.

Exe stance for extra damage and highlighting everything in smoke, lights out, and pox gas. Only taking counter fire because you want to be able to clear rooms of gunners on lower difficulties and the higher you go you can swap to highlighting reapers and ogryns.

Taking demolition team because you're the elite killer and you'll get back your grenades this way.  Tactical awareness keeps your ultimate up even without ability cooldown on curios.

Rending Strikes and bring it down for crushers and reapers.

Deadshot and precision strikes because you're headshotting things and want crit and have stamina. Crazy concept.

Shock trooper makes this build work so you can shoot anything you see. Kill zone for the extra damage.

Marksman's focus stacks are important to maintain because finesse gives you bonus crit damage so you can one shot gunners and shotgunners in the body if you crit. You will crit because you have all that extra crit chance and it stacks for every second you ADS.

Tunnel vision is literally the most important node in this build. It lets you keep shooting through the stamina degen of deadshot as long as you're hitting heads. That's why we take counter-fire to outline gunners. Headshot every ranged lesser and gunner that you can see, and you can maintain exe stance, charge a shot for an ogryn or reaper, and keep your stamina up.

Long range assassin and chink in their armor mean you can one shot reapers on a charged crit headshot, and if you take rending strikes over the toughness boost you can probably one shot a crusher too. Idk been a while since I tested this build.

Playstyle:

Sit just behind your allies, giving them ammo, throwing a grenade if they're getting overwhelmed by ragers and maulers, but your main job is to check for gunners, then ADS (not holding it constantly, that's how you run out of stamina and ruin your damage and crit and leave yourself unable to block in melee) and shoot them. You can easily one shot ragers and maulers without many or any stacks of marksman focus up to auric, and your boss damage is insane. You shoot the big things and elites.

Alterations:

If your aim isn't that good to be scoring constant headshots in melee, consider taking the mk iii shovel with the same headshot blessing, because all you have to do is hold your crosshair at head height, and use push attack into 2 light attacks, and repeat. It does the rest of the work for you, but it is considerably weaker damage. With a thrust blessing you can one shot mutants and ragers on auric with a charged special attack. If you take the 15% melee damage OR rending strikes for 10% rending nodes at the bottom of the tree, you can one shot dreg ragers.

If you find yourself taking too much damage in hordes, take 5% toughness per kill up the top in out for blood, and 10% per elite/special and 20% regen over 10 seconds in confirmed kill. Also consider lowering your number of stamina curios, and taking toughness boost in the bottom of the middle tree should you need it. you can max out at 270 toughness, should you really need the extra survivability. If you hate the weapon swap speed on the helbore, take 50% weapon swap speed in one motion.

As you go up in difficulties, and especially for the modifier "mostly ranged enemies" you will want to consider a few things - a faster charging helbore, smoke grenades, and the decreased charge time blessing. These will really help you be able to eliminate whole encounters full of gunner spawns quickly.

If you can't hit the head reliably in melee (60% weakspot rate) then consider taking duck and dive, and swapping your shovel blessing from take a swing to uncanny strikes. You get 15% melee damage so you can more easily clear hordes on you, you regen stamina when you dodge so you can continue blocking and pushing, and you probably also struggle to maintain stamina from tunnel vision, so can just spam dodges when your stamina starts to get low on top of the headshot damage. Up to you where you get the points from, but I would suggest opening salvo and chink in their armor, so you can still clear gunners. If you're still taking chip damage in hordes, drop a stamina curio for toughness, take toughness boost instead of rending strikes, and pick up trench fighter drill for attack speed with competitive urge replacing bring it down, so you can more easily horde clear. You don't have to commit to a purely ranged playstyle until you're used to surviving in hordes, and can more accurately position.

If you find yourself having to sprint between positions a lot, duck and dive is your best way to regenerate stamina, and the melee node before it gives a good bonus to horde clear. If you still need extra horde damage because you aren't in the right place at the right time, or your team keeps leaving you behind, desperado and skirmisher are an easy damage bonus as well. Depending on how easy you find it to fight hordes on this build, I would strongly recommend swapping to stamina regen on curios, but if you're finding you have to block and throw a grenade every time you're surrounded, it could be worthwhile sticking to block efficiency. If you're struggling even harder just to get a hit off, swap to a tac axe and try decimator and shred blessings, for power and crit, and pick up reciprocity instead of duck and dive for extra crit chance. You will chew through horde enemies at that point.