Miri Says Looting Starts Shooting Starts
 Arbites Build - Warhammer 40k: Darktide 

1. This is going to feel squishy compared to some of the melee builds when you don't have Castigator going. The axe is meant to let you kite around waiting for the chance to do that again but if you need a Suppression Shield with Block Efficiency as an alternative that's an option. Whenever Castigator is up you should feel fine. Don't be afraid to turtle with your dog while you let Man and Cyber Mastiff get you back to full, and rely on blocking, pushing and dodging to buy time for Castigator even when playing with the Taxe.

2. This is very gun-oriented. I think either the Combat or Exaction Shotguns are best for this, but I've used this with basically every form of Arbite legal gun. Knowing how much you like Bolters, that's what this one uses. If I do a more marksmanship version of the Bolter or a Vigilant, I modify as follows: Soulguilt Scan (replace Priority Endowment) and No Lenience (replaces Judicious Efficiency). Alternatively, for a more dakka oriented setup of the Bolter or another gun, swap Efficient Killer for Blessed Armament.

Bolters are a very fun and balanced weapon that can work into a bunch of playstyles; Pinning Fire is probably its strongest overall blessing, and pairs naturally to Cavalcade in builds where the bolter is coming out to, at the most restrained, typically fire in short bursts. When you do this playstyle, accept that your goal is to try to win the fight conclusively within about a magazine or so. If you've dropped two magazines and the fight is flatly over rather than merely now being won, you've use too much ammo.

I prefer to play around Surgical + Shattering Impact or Puncture to meter out ammo more, allowing me to fire it throughout an entire engagement. I still have an amazing magdump option there, but it's no longer the only ideal way to use the weapon. This is ultimately the joy of the bolter. Experiment often with its Blessings and the different ways of using it; there is often no one right way to do it because the weapon is flexible to account for both playstyles and situations.

3.  Arbite as a pure ranged experience is, IMO, infuriatingly, one of the best in the game and only held in check by the fact it absolutely chugs ammo. Be mindful of that. Very easy for it to be a sugar rush where it does wild damage but the show's over if you're not finding ammo or are being bad in your shooting. The Bolter is already a common offender here. Accordingly, this build really, really shines with teammates who have no interest in competing with you for ammo. Thankfully that's a lot of them! The most common meta builds for Ogryn is melee tank Ogryn, while Zealot's whole identity as a class is to use melee weapons, and Psykers often use staffs. I'll say a full 50%+ of the time you'll have no one compete with you for ammo. If you do have other ammo hungry players though, be prepared to modify your playing style to account for it.