You put them in a pot and apply heat until the lead melts and runs out, then you pour the lead into molds to convert to cast bullets. Unfortunately, the jackets will be wasted.
Perhaps you are wanting to convert load data. Unfortunately, unless the bullet bases seat the same distance into the case as the jacketed ones, the pressure dynamics won't parallel one another very well. Is there a reason not to simply use cast bullet data as a starting point?
