New Vet Run and Gun
 Veteran Build - Warhammer 40k: Darktide 

Ranged Weapon - Any Infanty Autogun. I think Columnus is probably the min/max winner, but I personally enjoy the Graia so much. This can also be played with the shredder pistol, but will become slight more norrow in what it can deal with. 

You can also replace either blessing with raking fire, which makes good positioning even more fun.

Melee Weapon - Any axe works well with this build. Rashad is arguably meta, but I really really really enjoy the attack pattern of the Achyls with all the finesse we are running around with. I also love running less popular weapons, so take that with a grain of salt. You can really run any weapon withh this build, just use your specific melee preference. I

Gameplay - This is a mid/close range special agent style build (with enough range to deal with annoying snipers as needed). You will be swapping weapons often, but purposely to make the most of our weapon specialist bonuses. Either weapon is a good solution to most problems, so its ok to have our gun out until a bit closer range than you may be used to. One big win that many people may not have seen yet is that accuracy and sway are significantly reduced by the attack speed bonus of Ranged Specialist. It makes infantry autogun absolutely sing. Swapping effictively will have you mowing down specialists faster then anything else I've played.

It relies heavily on positioning, using infiltrate as your clutch button. You get all kinds of bonuses from infiltrate and this is really a big part of our gameplay. Your goal is to sneak up behind the specialists we use to shoot from far away with our lasguns. The 90% threat reduction gives you 10 second of free massacre pleasure, with pumped up damage and defenses. And you have two charges, just incase you need to bail back to your team. 

Your job and target priority is to handle specialists and scary bigs first, sometimes leaving coherency to do so, before RETURNING to your team to help manage the hordes. You also should be paying attntion to downed teammates, since a good revive is just about the most value you can get out of an infiltrate..