Crash shot training is easy though, or you have a- mod, it's just literally 4 clicks every 15 minutes or so.
Just go to TNN and trap a zombie and start manually press the crash shot key or put on auto combat with modifications.
Crash Shot is far from being hard enough to train to require mods. I've trained it twice now, and the only "hard" part is the ridiculous amount of times you have to use it to rank it up.