I'm lifting an old thread, but I just love the designs from the Larsen family, they were creative!
This is a shotgun designed by a Norwegian bike manufacturer in Belgium and a Swedish friend - August Lefredius Larsen. August took over running his father's Belgium gun works (Hans Larsen, Larsen & Fils and Larsen rifle Co). As the models they produced (mainly single shot falling block, ultra high quality & precision target rifles) started to be somewhat outdated and too expensive, the facility closed down in 1887 and August started up with bicycles, but designed guns on the side.
I have seen some of his Belgium long-guns, they are as weird as his father's were and really rather intriguing.
The picture shows some of August Larsen's father Hans Larsen's designs.