Focus mutations to stumble lock them and apply your +25% dmg debuff. After Quick Kill + Hunker Down use the 90% percent accuracy while crouching to snipe mutations and your wider spread while standing for better horde clear. Weapon Scavenger is there to help increase the odds of finding higher rarity TAC-14's. Ideally you'll want a long barrel, Reload speed + stumble mag, and a +movespeed stock.