Dean is correct. 'Rough forged tubes' were matched at the maker's in Belgium, and it is quite difficult to identify the pattern until finished and colored.
Nov. 30, 1895
Sporting Life
http://www.la84foundation.org/Sports.../SL2610011.pdf
"The Gun Making Industry How Shot Guns Are Made and the Process Through Which They Pass Fully Explained"
The beginning of the manufacture of a gun is the barrels, and it is generally known that no barrels are made in this country except the rolled steel, which is used on the Winchester gun. All gun barrels are now imported, although an attempt was made a few years ago to produce them in this country, but with only partial success. England, Germany and Belgium supply most of the barrels, the latter country doubtless producing the larger quantity. All gun barrels, whether imported direct from the makers in Belgium, or through an importer in this country to the gun manufacturer, are received in rough tubes, which very much resemble a couple of gas pipes, but being somewhat larger at one end than at the other.
These barrels or "tubes" as they are called, are merely tied together in pairs, with small wire and 40 to 50 pairs are packed in a box.
The rough forge tube was made using 2-3 tube segments; thicker at the breech and thinner at the muzzle, so one can understand the difficulty in finding perfect matches.
Lots of examples of mis-matched tubes here SOME of which I believe were salesman's demonstration samples. Most were likely the result of a Monday morning after a long Sunday worship service at the pub
http://www.picturetrail.com/sfx/album/view/18015717
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