The French model 1892 revolvers I use to own all measured .323 in the grooves.
A .330 lead ball I'm sure wouldn't be an issue, so little lead that needs to be squished down, it'll do nothing but improve accuracy slightly from good rifling grip.
A charge of around 2.5GR's of unique would likely work.
Don't take my word on that one though, wait for the experts to show.