are some of the copper nickel coins of differant percent such as some may be nickel plated copper while others are actually the two metals mixed into one combination metal POURED INTO THE DYE or vice versa COPPER PLATED NICKEL OR MAYBE EVEN MORE PERCENTAGE OF ONE OF THE OTHER SUCH AS 80 PERCENT COPPER 20 PERCENT NICKEL OR 50 PERCENT NICKEL ,50 PERCENT COPPER