A Bing search brought up two entries
Here's a recent auction sale on one
http://www.bonhams.com/cgi-bin/publi...aleSectionNo=1
If the link breaks here's the grist ofthe info;
Lot No: 235S1
A Larsen-Winterros patent 16-bore underlever gun, no. 2955
Engraved browned receiver, slide retaining some hardening-colour, well-figured stock (repair at toe) with pistolgrip, horn pistolgrip-cap and steel butt-plate, sling-swivels, horn-capped forestock, the circular browned damascus barrel with half-length magazine-tube and matt concave-rib
Weight 7lb. 14½oz., 13¾in. pull, 28¼in. barrel, approx. ¾ choke, recent London nitro reproof
The other search result is the museum. They have some interesting stuff!
http://www.thm-online.dk/perioder/26...&type2=&type3=