Another reason it couldn't be a RPM is that the punching of mint marks were discontinued after 1989. So any 1990 or new coins would have to be a doubled die to have a separation on the mint mark or Machine Doubling which I feel is true with your coin. It it were a doubled die other devices would be affected. Also nickels are more subject to die wear as the metal used is harder than some other coins. But I'm sticking with Machine Doubling on your coin.


















