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

Bruce posted this D3 refinished by Dale

http://pic20.picturetrail.com:80/VOL.../385835791.jpg

1900 GH D3 refinished by Craig Smith courtesy of Mike Stahle with a similar pattern

http://pic20.picturetrail.com:80/VOL.../389237144.jpg

Jerry: could you please post or send me a full size image of that 3rd pic, by jpg attachment, so I can crop, enhance and add it to the album?
revdoc2@cox.net and thanks!

Drew,

I will send it tonight.

The only examples of blackening composite barrels that I have witnessed is in Ithica Lefevers.
If you observe original barrels you will notice an overall Patina beyond the simple contrast. This Patina is not just from age, it is an intentional final finish that blends the composite pattern uniformly. The uniform darkening serves to de-emphasise the stark contrast of multiple patterns and non-matching tubes.
In our finishing process we refer to this last step as the "conversion step".
Barrels that are finished to the contrast only state are certianly very interesting but not truely representative of the methods used in original finishing .
Mismatched Ribands and anomilies are very common. Perfectly matched tubes are hand selected and usually reserved for higher graded guns.

Brad

For quite a long time there has been a DH for sale on. Gun rocker that is advertised as a possible factory error. The gun letters as a Titanic Steel barreled gun and it has the Titanic marking on the rib. But the tubes are Damascus.

I've seen that ad Brian and that one is truly an enigma.

Yeah. The rib matting is a little worn for polishing and such, but it does not LOOK to be replaced. The barrel flats do not have a "T" on them.
An oddity for sure. And a hard sell.

Brad,

Thank you for your answer. That explanation is what I was looking for, how 130 years ago these barrels with five different patterns could have been made presentable to the buyer who would part with his hard earned $80.

in a talk I had with dale Edmonds last spring , he was refinishing a set of lefever barrels for me and I asked him how they looked, he didn't like the way the tubes were matched but they look better than some of the other barrels he has seen. he is one of the best at his trade. so I wasn't expecting much when I got them back , when I opened the box my jaw hit the ground, they were wonderful, theres pictures in my gallery. I guess he judges
barrels a lot tougher than I do

Jerry graciously shared full size images, which are quite interesting. The breech shows poorly matched 'Oxford' Parker D3, both in the appearance of the scrolls, and the manner in which the iron/steel responded to the coloring

http://pic20.picturetrail.com:80/VOL.../408703320.jpg

EXCELLENT demonstration of the juncture of the tube segments toward the muzzle. From left to right:
1/2 scroll with (mostly) straight ribband edge butt weld
2 full scrolls with (down the middle) 'zipper' (wavy) welds
scroll with the straight weld between the two tube sections
2 full different scrolls with (down the middle) 'zipper' welds
1/2 scroll with (mostly) straight ribband edge butt weld

http://pic20.picturetrail.com:80/VOL.../408703319.jpg

Thanks Jerry!