Black powder and pre-1898 guns should be fine, but you should still consult a lawyer. Don't just take internet advice at face value...What about black powder firearms?
Could I (or is it possible) to get the charges expunged? Or am I pretty much sunk? What about black powder firearms?
Consult an attorney. It might take a pardon from the governor, but it seems nearly anything is possible in our legal system with enough money and the legal counsel it can buy.