quick explanation of different methods.
you win the lottery?? the older ways to do it are just as expensive in relation to the cost of setup today as it was way back when.
the price of machine tools has not changed and frankly i doubt it ever will. the only thing thats changed is the massive inflation.
back in the 1800's you needed the equivelant of a couple million in today's money to setup a rifling operation. you will need that same equivelant in money to etup whether your doing it the way it was done in the 1800's or the way its done today.