We've discussed this pattern at length in the past. Parker Bros. called it Laminated Steel. The tube makers in Liege called it "Toncin"
I'm astounded that the tube maker at Parker Bros. could create such a complex pattern with such artistry, and have no idea what the lopin looked like, but it much have been quite intricate. John Blaze was from Birmingham, I've never seen anything like this pattern on a British gun, and I wonder if Liege tube makers were brought over?
Later Belgian sourced Laminated Steel tubes were quite different
Nice collection of images of the pattern about 1/2 way down, courtesy of many here, esp. the "gold towel guy"
http://www.picturetrail.com/sfx/album/view/19406549
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