W. Collath Söhne double gun 16 ga, SN 22045
https://www.egun.de/market/item.php?id=18389528

Mauser rifle in 6,5x55, I would say an original mauser reworked by collath. nut sure 6,5x55 is original because the rifle got a new proof on 1997. maybe the original barrel was rechambered.

https://www.egun.de/market/item.php?id=18390678

original mauser SN is 28393