Drilling in No .3 what is close to 14 ga and 11,15x65R http://www.naturabuy.fr/drilling-w-collath-item-3047224.html

notice the damascus barrels what came out of fashion very quick after 1900 when smokless powder became popular so I think it must be a very early made gun

16 ga or No. 4 double gun for sale in russia
http://newhunter.ru/80-19-.-w.collath

another interesting drilling for sale in the netherlands
barrel in 16ga+16ga+8x57IR, the other 12ga+12ga +22 lr(I think a liner maybe in an old 9,3x72R barrel)

http://www.gebruikte-wapens.nl/producten...wisselloop.html