This coin is the wrong size for a penny and when i drop it sounds differnt . found coin roll hunting . i am doing pics of coins on out side ofvthe coin to show the size .
IMHO this is post mint damage PMD. It has been beat up badly. The outer edge ground down. Sorry to disappoint you.
that is because it is post mint damage, just from your pictures its obvious it is pmd. Somehow be it acid wash circulation wear ECT. your coin lost enough copper to make a different sound than other copper coins. weigh it take a pic of the edge