How would I enter the 179 depreciation thing for my new "used" tank?

OK, so a few years ago, TurboTax helped me file my taxes when I opened my tank rental business. Everything has been great the past few years and I've had no troubles filing.

In 2017, I bought a 1945 awesome hulking tank to rent and let people drive around the course. It is an awesome course and you can crush cars and everything.

Anyway, it is an old tank but new to me. But I just bought it, can I depreciate all of it or the 50% of it allowance? I just don't want to go to jail. 

Thanks so much!