Some post mint process has pounded on the rim to make it flat and start to expand.
This is sometimes called "Spooning" because it can be done with a spoon. Similar effects occur in arcade machines where the same coin is used over and over cycling between the change machine and the game machines until someday it escapes in somebody's pocket.
Also this effect can be seen in commercial clothes dryers - called a " Dryer Coin"
Search for those terms here and you'll find plenty of examples and images.
-----Burton
50+ year / Life / Emeritus ANA member (joined 12/1/1973)
Life member: Numismatics International, CONECA
Member: TNA, FtWCC, NETCC, EveryCountry (online) coin club
Owned by three cats and a wife of 40+ years (joined 1983)
Disclaimer: While a tremendous amount of effort goes into ensuring the accuracy of the information contained in this site, Coin Community assumes no liability for errors. Copyright 2005 - 2026 Coin Community Family- all rights reserved worldwide. Use of any images or content on this website without prior written permission of Coin Community or the original lender is strictly prohibited. Contact Us | Advertise Here | Privacy Policy / Terms of Use