This one is in the upcoming Dorotheum, Vienna auction:
https://www.dorotheum.com/de/l/6774777/

Bockbüchsflinte, Gebrüder Merkel - Suhl, mit Schrotwechsellauf Kal.: 12/70 und Lederkoffer, Kal.: 7 x 57R/12/70,

Very nice combination, pre WW2, I think, quite similar to the one I bought recently (and am still waiting to have it here in Switzerland....), but quite some more class in it:
note the better locking system with Kersten crossbolts plus underlugs
nice wood, probably bespoke fitting (the Krawatte or chinstrap hints to that)
loong barrels (68 cm / almost 27´´ for the Bockbüchsflinte
probably 75 cm / almost 30´´ for the extra shotgun barrels
on top of that the leather case....

I like these combos! But one is enough for me, so I´ll relax and just watch...
fuhrmann