Found an AYDT Schuetzen in 22 LR.  It's barrel appears to have been relined.  I was curious about the original caliber.  Any help with these barrel markings would be appreciated.

Mark

Crown over G=Rifled barrel
Crown over B=first proof
Crown over U=final proof
If it was relined in Germany there should be a crown over R for reproof after repair. The proof marks indicate it was made before 1939. The 5.3 might be the metric caliber, which would be 22 as the German measurement is land diameter not groove diameter. This is from memory without consulting my books.
Mike

Mark
I don’t own an Aydt, but the Aydt action has an internal hammer, so the rim fire block would have a different hammer and block from the center fire. I have a 22 schuetzen and the barrel is marked 5.3. I would guess your rifle was always a rim fire, the serial number match would confirm that. To convert a center fire to a rim fire would require a different block, hammer and extractor. If your action has a different serial number than the block, that is of no concern as that is common, apparently the factory paid little attention to mismatched numbers. 
Mike