Join Date: Jan 2017
There is an important message from 1618 Bohemia which speaks about marking on cannon balls.
.. Trćka – bohemian nobleman and owner of several iron foundries (“Hammern”) on Sazava river, which was on the line between Habsburg army and Bohemian rebel army in 1618, is accused by nobles that he is making and selling cannon balls to the enemy Habsburg army.. and even that he marks them with his mark ... (cited from Skála ze Zhoře: Historie česká, 1626, version published 1984 by Jos. Janacek)
Unfortunately there are no known balls survived with such a marks..