doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Damascus pattern variations..

The most likely explanation, is that the steel used in that rod had a different alloy content, causing it to have a finer grain structure and become more reactive to the solution. Why it is different, is a quandary. Different supplier than the other rods, different batch of steel used???

Craig is correct that, at least in some places, the twist rate seems slower than the other rods. A lower twist rate can cause the lines in the pattern to be broader.

Another possibility is the number of layers used in the darker rod. It looks to be about 15 layers. The image isn't clear enough to accurately count layers in all the rods. If the other rods were made up of more layers, this would also cause the lower count rod to appear darker.



It was my understanding (perhaps incorrect) that barrel tubes were mostly finished on the outside, and bored and chambered before they were marketed to the gun manufacturers. This was necessary in order to proof them before sale.

Having the tubes ground to near finished wall thickness for proofing, would allow for viewing the patterns to select closely matching patterns for paired tubes.

That all makes sense.

Now, back to my earlier iteration, I'd contend that the effect was intentional, since it's observed in all ribband sections of the tube. If it was unintentional or a mistake, it should be localized to one section.

I was hoping DocDrew would be able to provide a specific name for this feature.

Regards
Ken

An added note, at the end of the manufacturing process, the tubes were coated with Sulfuric Acid before shipping. I use this myself for the initial etch. This creates a "skin" on the tubes and makes the pattern very visible. This would aid in matching decisions for tube sets.

Regards
Ken

On most guns "Made in America" you will not find the definitive proof marks. On some you will find the provisional proof marks, but not all. none of my Lefever guns have any proof marks at all, though I know that some have the Belgian provisional marks. The provisional proof was a proof applied to a rough tube, un-finished on either outside or inside & un-chambered. Definitive proof was applied after the barrels were essentially finished & had been joined together.
My feeling is that American makers bought the tubes "In the Rough", bearing only the provisional proof & then finished them to their purpose. In the process of finishing many lost enough metal on the OD to lose the provisional mark.
If you find a set having definitive proof then that set of barrels was jointed & finished in Belgium. I cannot say absolutely that none were, but I have yet to see a set of barrels from a noted American maker carrying these definitive proof marks.

Thanks for this information 2-piper!! I should study the proofing process more. I can't envision how they contained the proof load in a rough tube.

Ithaca Gun Co. tube storage area. Some appear as joined sets while many others appear to be stored as individual tubes.

Walt, great picture. Do you have an idea of the date ?

It appears to me that the variation in your barrels is just the result of using a ribband that had a differing composition of iron and steel. Whether this was intentional or accidental is a matter for conjecture.

I'm interested in what you said about rough barrels having a coating of sulfuric acid applied before shipping. I'd assume this would have had to have been neutralized after bringing out the pattern, or all you'd see is a coating of heavy rust.

It has always been my understanding that what Miller says about the proof process is essentially correct. I believe the tube are rough bored for the provisional proofing, but they are not chambered. But I have never been able to find out exactly how the proof houses breeched or contained the proof charge in unfinished and unchambered barrels.

Leave it to YouTube. Apparently, a temporary breech plug is fitted during initial proof. Here's a link to the video. For some reason, I can't attach it here:

https://www.youtube.com/watch?v=f3aHnxsj7y8

Please enlighten.... What is a "rolling mill"?