To answer John's question
In 1865, Ethan Allen recieved a patent, #48249, for twisting, winding, and welding damascus shotgun barrels. One the witnesses is Sullivan Forehand.
http://www.google.com/patents?id=hTIAAAAAEBAJ&dq=48249&jtp=1#PPP1,M1
"I take a number of sheets of metal, of hot iron and steel, and lay them up alternately first a sheet or bar of one and then a sheet or bar of the other and when I have a sufficient number together they are subjected to a Welding-heat, and thereby welded solidly together. I then roll this down into a small bar and again heat it, and put it into a machine and twist it, after which it is again rolled flat or partially flattened. I then cut this flattened bar in two lengthwise through the center, and put these together, keeping the outside edges together. I then wind them spirally (after being heated) around a round rod, keeping what was the center of the bar before it was last cut in two on the outside, then weld it firmly together in the ordinary manner, thus producing a figure on the exterior of the barrel corresponding to the twist of the inside of the bar."
"The figure of the barrel can be varied by the number and thickness of the layers and the twist given the bar, so almost an endless variety of figures can be produced, and make a very strong as well as a very handsome barrel."
One year later, Ethan received another patent for soldering the tubes together through internal flaming. Sullivan Forehand was a witness again. Ethan Allen resided in Worcester, Mass. at the time of both patents. He produced over 600 of his breech-loading shotguns of unique design in Springfield, Mass. between 1867 and his death in 1871.
