I've got a couple of firearms with barrels that must have been made by Richard's brother, Krupp Stahl...

...and my mate has one perhaps made by his sister, Fluss Stahl.

Apologies Nick, we really did get off track here!
Look forward to seeing pics of the rifle when you get image hosting sorted. I too like obscure/rare chamberings in vintage rifles but lack the courage to tackle the European stuff!