Note on the coppercoins site this quote:
Quote:
A small date hubbing over a large date hubbing shows in the date, LIBERTY, and in some areas of the motto. This die is also listed as 1960D-1MM-100.
This year the small date was replaced with the large date design. So the large date hub was used on the first hubbing, then a small date hub was used a different time. They didn't get the small date hubs away from the staging area and they go used by mistake. Thus the small over large date die was created. Then it was also a RPM when the mint mark was placed to high onto the devices. (keep in mind they used the mint mark punch quickly, thus creating so many RPMs this year)