I'd first suggest trying to sell it and then buy the 45/70. If you've dealt in guns any, you already know that a gunshop will not give you near what you paid for it in a trade. Another thing to try, if its legal where you live, is to go to some local gunshows and see if you can sell it to an individual. You'll get more for it and that'll put you that much closer to buying the 45/70. If you bought the 336 new, you'll probably take somewhat of a loss on it, but you don't have to take a beating. Good luck.