How could one side be a very weak strike and the other side be a strong strike? Think about it. If the strike was weak on the reverse, the obverse would have to also be a weak strike, right? As rockdude said, someone has filed, ground (grinded??), or otherwise removed the reverse of your coin. PMD.
That is a good ovbservation that is why i will always welcome your comments Hobo to learn about coins.
