For me, Daryl and Birdhunter50 have take the point the problem is not the dimensions but the quality and also in the old action the condition.
Xausa, is thinkable that the gun was born as a rifle and later will be made a shotgun gun pair or it is born as rifle with a shotgun replacement barrel?
Ps. The Krieghoff quality with other German double rifle makers is one of the few certainty, that I have.