Antique muzzleloading shotgun. Info/value?

[DMS1]

I would appreciate any info/value of this shotgun. One of the hammers doesn’t stay cocked but the click is there.

 

[MC One Shot]

To me it appears to be of Germanic origin possibly Austria. Any proof marks anywhere? Under the barrels?

 

[DMS1]

That looks like a B stamped on the barrel?

 

[mooncoon]

while my first vote would be made in Belgium, the relief carving at the back of the butt makes me think it was a better than average made gun. The engraving on the lock brings me back to Belgium. Locally shotguns are hard to sell so I would price it around $300

cheers mooncoon