Hammer gun 12G made in 1885 s/n 30 found in Moscow.
Double barrel set, but seems fluid steel barrels (ML Cockerill steel) made later, than damascus barrels by E.Heuse-Lemoiner.
Pay attention mark 17,0 on damascus barrels. 17,0 means bore diameter in mm and actually it's 16G. As soon as these barrels been sold in white with the first provisional proof only, Matska overbored barrels till 12G later.
Steel barrels got very unprofessionaly made sign on top of barrels 'F.Matska in St.Petersburg' and it's probably means it's been fitted not by Matska, but by somebody else. OR this sign badly restored.
http://i032.radikal.ru/0904/e3/1649841ab05b.jpghttp://s40.radikal.ru/i089/0904/1c/81db8a61239e.jpghttp://i068.radikal.ru/0904/e9/138418949cb0.jpghttp://s45.radikal.ru/i107/0904/9c/25c2daf35a20.jpghttp://s39.radikal.ru/i083/0904/e6/661a8d7e561f.jpghttp://i053.radikal.ru/0904/8a/4093a2181534.jpg