Thank you soooooo much. I think you're right.
Obviously I made a mistake with the size. 30 centimeters would be quite a big coin
It's about 35 mm.
It looks like some of the edge is worn off and it's slightly bent, which would add a little to the diameter if flattened.
The weight difference I believe can be due to loss of material and the hole that was punched out.
All things considered I think you nailed it!
Unfortunately we'll never know the date.
Obviously I made a mistake with the size. 30 centimeters would be quite a big coin
It looks like some of the edge is worn off and it's slightly bent, which would add a little to the diameter if flattened.
The weight difference I believe can be due to loss of material and the hole that was punched out.
All things considered I think you nailed it!























