Proof 1973-S Kennedy Half Dollar
Flip-Over Double Struck
2nd Strike Off-Center
NGC PF 68 Cameo
Although there are a few known double struck proof Kennedy Half Dollars, this one is obviously the finest known and one of the most spectacular U.S. proof mint errors ever discovered. It is hard to imagine a proof double struck U.S. coin that is more dramatic and that has this level of eye appeal and rarity.
Proof coins are struck by technicians who hand feed the blanks into special presses. They are produced, examined and packaged using extreme quality control. It is very unusual to find major proof errors. A few broadstrikes, off-centers, double strikes (in collar) and off-metals have been known to be found in sealed proof sets. Proof errors are aggressively sought after by many error collectors.
A very small group of Proof errors recently came from a collection that was auctioned by the State of California. The U.S. Secret Service inspected and released this collection to the State of California determining that it was legal to own. The State of California then auctioned the collection and it has been dispersed since the sale.