So, this isn't anything new here, just an updated version of what others have posted. There are two files, one with half the normal durability rate and one with unlimited durability. 

INSTALLATION
1. Navigate to the game's file directory (right-click in the Steam library, then select properties, then Local Files, then Browse Local Files).
2.Enter the 'DW' Folder and copy the Data3.pak file and save it somewhere else. (It isn't very big, and this is making sure your original file is good to go)
3.Drag and drop/Copy and paste my file (named 'Data3.pak) into that 'DW' folder and overwrite when it asks.
4.Play the game, hitting as many zombies as you like.

If there are any questions, feel free to ask. I didn't use anyone else's work, I just made this myself. Hope your guys enjoy it, have fun!