Unusual Dark Finish:

[Bruce P Bruner]

Of my many Damascus shotguns these barrels have the most unique almost gun blue finish. It could just be the outdoor lighting in the first photo, though they are dark regardless.
I asked Breck about them, he thought perhaps exposure to UV light. I didn’t think these barrels had seen the light of day for a very long time, based on how much oxidation I removed with an oily Frontier Pad. It wasn’t red oxidation, it was black.
They sure are strikingly different from what I’m accustomed to. I wonder if they looked like that 116 years ago.

[Dean Romig]

With that much case color remaining it wouldn’t surprise me if those barrels have their original factory finish.





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[charlie cleveland]

nice barrels...charlie

[Drew Hause]

Beautiful barrels Bruce.
E. Heuse-Lemoine of Liege wrote in 1884 that the pattern coloring and contrast was dependent on the source of the coal, the source of the iron (and alloys present), and whether charcoal, coke, or coal was used by the smelter.
And of course the chemicals then used for blacking.

It has been suggested that higher levels of manganese in the very low carbon steel yield a darker black, or maybe related to one of these (toxic) chemicals:
Muriate Tincture of Steel (Red oxide of iron [Ferrous chloride] and muriatic acid)
Sp. Wine (Methylated Spirits or methyl alcohol)
Muriate of Mercury
Nitric Acid
Blue Stone (Copper sulfate or Blue Vitriol)

[Aaron Beck]

Ill throw my opinion in here. If you look at the barrel flats of most damascus guns you see contrast like these barrels but the field is uniformly darker than we might expect. This could be due to less wear, less sunlight, or less carding during the finishing process, or it could be the originals were uniformly darker than we now expect. Some allegedly original examples have been posted here which bear this out, but its just my theory. Its also highly subject to material composition and chemical process as stated above.