Ah yes, the infamous "Big Crowns". As 2-Piper mentions, these are not part of any national German proof regs, at least according to Engelhrart, Kennett, Wirnsberger or other reference I have seen but are fairly common on pre-WWII German guns, particularly Sauers.

Has anyone seen one of these big crowns on a gun _not_ from Sauer? I have a 1905-ish Sauer double with one big crown that is also marked "Prussia". There's always more to learn....