Chemistry, Metallurgy, Math (Trigonometry, Geometry), Machine Tool operation, welding, all as preliminary to a gun smithing school, usually available at a local community college. Chemistry and perhaps metal shop and machine shop (If not in your high school proper, in a Skill Center your H.S. partners with.), are available in your high school. Take advantage of the FREE classes while you can...the expense of college education has gone through the roof.