Hate to agree with the
PMD opinion.
The reverse is what is referred to as a vise job where two coins are squeezed together leaving a mirrored imprint on both coins involved. The circle pattern on the obverse could be a work surface like someone above mentioned a press work base.
Edit: on a side note after looking at your
LMC again, it was squeezed so hard that I'll bet the diameter even increased from the 19 mm it should be.
Check out my counterstamped
Lincoln Cent collection:
http://goccf.com/t/303507
Edited by chafemasterj
06/06/2018 09:34 am