Can anyone identify this gun?

[magic mike]

The discharge end of the barrel dimension is 0.334". The breach dimension is 0.470". It is center fired and smooth bore. On the barrel is “ 1 gr I.G.P. n/71”. Below that is “6 gr BI.” On the side plate where the lever is to break open the barrel are what I believe to be two proof marks. One is a crown with “U” under it which I believe to be German. Next to it is another proof mark with an insignia with a “B” under it that is a ?? The sights on the gun would be more along the lines of a rifle vs. a shot gun which I originally thought it was. Any help would be appreciated. I have searched the internet and originally thought it to be Belgian made. There were also some comments regarding decommissioning in England. There are no other marks on the gun to identify. Nothing under the forearm or butt plate.

Thanks,
Mike

 

[Tommie]

Flobert?

 

[Depart123]

It's called a "garden gun". Many different manufacturers made them, including Winchester. They were popular in Europe for back yard pests in neighborhood type settings. It is simply a 9mm shotgun. IIRC there were both rimfire metallic type crimped cartridges, as well as some centerfire paper cartridges.