triple barrel crit goblin
 Hive Scum Build - Warhammer 40k: Darktide 

triple barrel go brr: desperado doesnt have good synergy with the double barrel so its better to go stimm supply to spam the reload speed and get to the insta reload effect without using both barrels blessing. this unlocks the ability to use the scattershot and flechette combo, which will increase out damage by a butt ton. finally we grab the finesse strength combo to increase our crit damage (which is almost all our shots) by 50%. needless to say you end up nuking your way through the game. we go for triple toughness this time since you wont be on the frontline and wont need to worry about overheads too much. 

remember if you dont have a vet or zealot you can switch to the crit chance one for more bleed and killing, but since you have scattershot and dependency, your crit chance is huge anyway so its not required

melee weapon is dealers choice. i put down the knife but anything that give mobility, defence and armour piercing to deal with chiefs and crushers (shotgun can melt a twins shield at least) will do the trick. this includes both knives, crowbar, bonesaw, shivs, blue/gold tax, axe and if your feeling risky, the chain weapons

single shot only unless you are onetapping a mutant before he runs past. this one is a hard sell on havoc 40 but it can work just fine