Poltina (50 kopek) 1812, silver .868, weight - 10,36 g. St. Petersburg Mint. Mint master Michail Fedorov.
British Empire war in US and Napoleon invasion in Russia during the same year? Can't think of anything else related to this coin.
Spot on Taxidermist. This is actually an overdate 1812 / 1 with reengraved mintmaster from MF over FG. Quite neat to be honest - while it might not be rare, I don't think it's common either.
Very nice set and laid out great. Here is my Russ set. https://picasaweb.google.com/Ripley44mag/RussianAndEasternEurope#