Either one Franc
Shooting Simplified, James Dalziel Dougall, 1865
There are various kinds of flaws in barrelswhat are technically termed
grays. They are those little specks in the ironfrom rust showing more upon them than upon the smoother surface.
The Gun, W.W. Greener 8th Edition, 1907
The numerous twistings and weldings of gun-iron rods and ribands are fully detailedand it must have occurred to the reader that the Damascus barrel is one mass of welds from breech to muzzle. This is so. Unfortunately a certain amount of burnt metal, or scale, is imbedded within some of the welds, and in the finished barrel this fragment of scale forms a greywhich will not colour in harmony with the other part of the barrel, but is made more apparent by the finishing processes of polishing and browning. These
greys may appear some time after the gun has been in use, the hard metal composing the barrel being eaten into by rustThey are developed in the inside by the chemical action of powder gases, and are almost ineradicable. The harder the Damascus the greater the liability to greys
They are a cosmetic flaw, but not felt to be a safety issue

