Vet Havoc 30
 Veteran Build - Warhammer 40k: Darktide 

All rounder. You are in charge of Ranged enemies. Weapon swapping and decent mobility.

Horde Clear:

Combo 1: Push + Push attack (horizontal) + light attack (horizontal)
Combo 2: Push + Push attack (horizontal) + HEAVY (diagonal) + light attack (diagonal) + HEAVY (diagonal) repeating
What i do: Combo 1 + Combo 2 back to Combo 1 + Combo 2

This helps split up stamina use a little bit. Of course sometimes ill just spam Combo 1 if the situation allows it because its easy.

Use the pistol and its explosion radius to disrupt hordes. Dumping the clip can clear a horde easily. At the very least it will reduce the hordes numbers greatly and disrupt them (stagger and split them).

Specialists:

I just use light attack spam. There is great damage in this.
Pistol when they're far away.
Mutants can die from a simple: Light attack + HEAVY (uppercut) i use this for high damage on maulers when i need too.

Elites:

Crushers - always use a krak grenade. If i have no Grenades, dump the clip in your gun. Your pistol here can kill a crusher in 6 - 7 shots (Clip holds 7) i use the pistol often.
Bulwarks - single Bulwark (Pistol) more than one Bulwark (Grenade) then Pistol follow up
Gunners - Pistol
Ragers - Pistol.     Scab Ragers - Pistol.     PACK of Scab Ragers - Grenade to disrupt and kill the first 1 or 2, then pistol follow up
Maulers - 2 or less - Pistol.     2 or more(PACK) - Grenade to disrupt and kill the first 1 or 2 then Pistol follow up.

Anytime the Sword is on cooldown is the time i use my pistol most times (situation depending of course) then swap back to the sword after the clip is emptied (add a reload if you can before going back to the sword so its always ready to swap to) and the sword will be ready again.
DO NOT try and take on waves of Ragers and Maulers with your melee alone. If you have no Grenades, just pull back and dump the clip, this will kill multiple and the explosions will disrupt the pack a little. THEN switch and melee or just reload and dump the clip again (reloading and shooting is preferred). This is built around both melee and ranged not just melee.

Boss:

You have to rely on grenades and pistol and sneak in melee attacks where available. You can do good damage but you do need your team to help as i find the Veteran to be quite squishy.

THE KEY IS TO KEEP "SKIRMISHER" UP (Slide 4x , you get +25% damage)
Skirmisher applies to both your pistol and Grenades. Dealing great Boss Damage. If you can monitor "EXPLOIT WEAKNESS" that also gives an extra +20% damage to Grenades and Pistol but is harder to manage since it is activated on critical hits. But is possible when you get in the flow of things with this build. (look for a critical hit as you fight the hordes around the boss, once you see it proc, try and target the boss with a grenade) Keep moving.

Build:

I sacrificed keystones so that i can get the extra weakpoint damage on the bottom left and also the base +10 Toughness Damage Resistance. Also the +25% ammo since we use our pistol alot.
They are all more valuble to me than the keystones available. This is built as an ALL ROUNDER remember.
I put stamina on the sword and stamina regen and block cost on the curios because the Veterean Sufferes the worst when it comes to Stamina regeneration time. So he needs the assistance so you can operate freely in melee combat without worrying a whole lot about your stamina. Keeping in mind our main horde clear combo comes from a push attack.

Bomber resistance is a personal choice because they're inconsistent with how they work, so you can change that out. But i leave it, bombers are a pain in high havoc and hit you more than you realize. Whether it be your fault, or a horde had you trapped, or your teammates didnt push it. (you thought he would because hes closest)

I dont bring revive on my curios because i use my Ability for instant revives. I dont bring Combat Ability regen because Stamina , Damage Resistance and Blocking is more valuable to me than saving 3 or so seconds on my ability.

RELY ON YOUR PISTOL WHEN YOU NEED TO. IT DOES GREAT DAMAGE AND IS A GREAT SECOND OPTION IF YOU HAVE NO GRENADES AVAILABLE. Seriously, dont neglect this little canon. And the swap speed is good too.

I chose Carapace for the sword because we're aiming for headshots and most enemies have Carapace helmets. Atleast the ones that matter. We already do good damage to flak without the booster too. I put stamina on for the same reasons as before, so we can operate in melee a bit more freely.

Simple to use, high damage build with good utility.

Feel free to suggest some tweeks but this is my main build and it works well for me. Ive completed 2 Havoc 30s with it. But haven't tried higher. The Veteran class in general has to work hard to survive in my experience. You do need good teamwork as with most classes

Note: dont expect a build to carry you, you still have to be good.