Got a reaction from a Russian friend:
This is a coin of tsar Mikhail Fedorovich (1613-1645)
Denomination: Kopeck
Mint: Moskow
Date: ~before 1620
Legends:
Obv: (Moskow, in two lines)
Rev: (Tsar and Grand Prince Mikhail Fedorovitch of All Russia)
Lit: A.S.Melnikova, dies 3-9
Kleschshinov and Grishin 340, dies 1-12
Rarity: common
My Russian is not good enough to judge if the text is correct, but your coin would have looked something like the reconstruction on the picture. The Mint mark M under the horse becomes visible once you know where to look.
The rider is St. George, making dragon kebab. Russia used this device long before Pistrucci put it on a British coin. The device is still used on the Moscow arms (picture) as well as on on the federal arms, where it is the breast shield of the spread eagle.
Peter