Kraxton's 'Braced Tactition' Focus Invis
 Veteran Build - Warhammer 40k: Darktide 

A build created with the synergy between braced autogun and Invis on Veteran in mind. When you pop out of invis, you suppress everything around you...thusly you get free bonus damage on everything around you with Ceaseless Barrage! That combined with Close Quarters Killzone means you just melt everything around you, and none of it even knows you're there thanks to low profile. This lets you just walk over the battlefield with bullets, while also not having to worry TO much about gunners, so long as you can get enough specials to spam the ability relatively repeatedly. 

I then throw on Krak grenades to help with boss damage (and since it goes from 2 to 3 with grenadier), and Combat Axe to decimate armored targets. Decimator + Thunderous drops anything in front of you with the Axe III overheads, while the push attacks can still be used to clear the wave in a pinch. This all being the reason I take Trench Fighter so as to help stacking it all that much faster, so you can leave the kraks for the pesky bulwarks. 

Beyond that, just mark all the targets you see, and 'bring them down!'.