Shovelshooter - Crush Crushers
 Veteran Build - Warhammer 40k: Darktide 

For your infiltrating Mauler mauling and Crusher crushing needs, Limbsplitter Thrust foldable shovel gets the job done - no buffs needed to one shot a mauler at 3 Thrust 4 stacks, Agile Engagement bump gets you what you need to one shot a Crusher.  Lawbringer shotgun is versatile vs everything softer than Carapace - the foldable shovel doesn't do the best DPS vs Unyielding so Krak Grenades are boss busters. Easier access to Man-Stopper critical hits with Unlocked and Unloaded means you can shoot power swords into crowds and rack up the horde clear. Vote early, swap weapons often.  Chainaxe is a decent alternative to foldable shovel though it doesn't have as good burst damage as the shovel due to need to rev the axe.  All three shotguns work great as a primary, as do the braced autoguns and recon lasguns. Double barreled shotgun is also a hoot - Man-Stopper and Deathspitter are a good play.