Legit case? (not mine, from web)
At least a funny and truthfull headstamp!
Looks like it has been fired.
Would expect duck to be plural
Doubt a legit Punt Gun round
There was always a guy at the Lincoln, NE gun show that had one, but didn’t want to sell it. He always said it was a joke.
Obviously not a period-correct cartridge but maybe a machinists-shed-made one for actual use in a punt gun?