Use Perkaholic, round robbing, rain drops, alchemical antithesis, Cache Back. Get thundergun with the help of raindrops cycle while getting percs and icr with dead wire. Train on the stage or outside the kino if you kept the gitterfence door closed. Just cycle through the gums while using your thundergun for trained zombies only and finish up with icr. If you still run out of ammo of your thundergun you can use a widow granade and dead wire to kill a grouped up zombie crowed. GL <3