All about the brrt
 Veteran Build - Warhammer 40k: Darktide 

This build is most focused on shooting everything ever all the time. Backed up by the best combat axe in the current meta. 
You need to have decent recoil control and aim to make this work, as it is heavily dependent on crits, which you will have near unlimited of on a recon rifle with a high ammo stat. People dog on Marksman's Focus and I agree it could use some real rework but it's still usable it's just not busted like some abilities. You'll be able to keep executioners stance up for as long as any engagement last so long as there are ranged unit's to shoot. And you'll have full stacks of marksman's focus nearly instantly just by strafing any of the mobs at head level. This will give you highly increased toughness regen, while also giving you a prolong damage boost. I find I can melt most any target so long as I can reliably hit it extremely quickly. Things that lunge and weave a bunch like the deamonhost are harder at first but still very doable to melt with this build. 

It might seem counter intuitive but this build works best at shorter ranges, as you get the most out of the damage buffs that way. On higher difficulties there will be enough elites and specialist that you'll be maxing out the "Confirmed Kill", "Survivalist", Executioners Stance" and "Tactical Awareness" abilities. Plus you'll be able to move pretty freely so long as you're weakspot hitting the mobs that come with those waves, leaving no need to worry about the marksman's focus stacks.