If the coin weren't in BU condition and showing lots of die flow, I would almost think it had been encased. The rough edge makes me wonder if this wasn't struck on a blank instead of a planchet, but it's hard to find extensive information on coins struck on blanks. Coin mass is normal.
I do know that weak strikes can leave a shelf around both rims because the strike doesn't completely reshape the protorim established by the upset mill.


