Harry and anyone who has concerns about what has been printed on shell boxes for a hundrrd years or so…. And even to this day RST prints the same thing….
Originally it was because most of the biggest ammo manufacturers were owned by or in cahoots with firearms manufacturers and this ploy was developed in order to sell more new guns with the newer fluid steel barrels , but today and even in RST’s case it is all about liability insurance. The insurance companies demand that be printed on the box to reduce their exposure to lawsuits.





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This has been hashed out on multiple site, and publications for years, and in the absence of any of proof of that, I think it comes down to urban legend.

It's always been generally accepted that the real reason was that the advent of smokeless powder drove the ultimate introduction of steel barrels. Hand loading in the days of only damascus steel barrels was very common, and those blown up barrels that generated the bad press was due largely to the lack of enough instructions and cautions relating to The weights and volume of powders. Charging a gun with smokeless powder of the weight, or volume of the black powder charge previously used was the real error, and not the material the barrels were made of. Sherman Bell knew this, and simply saying so wasn't enough for him, so he proved it, beyond any reasonable doubt.
I think the warning on RST may be more Morris, than the insurance company. You don't see other shotshell boxes with the old 'You'll blow your gun up' warning.

Actual tensile testing by METL here in Phoenix, a certified metal testing lab is here
https://docs.google.com/document/d/1...hfDxmrNAU/edit

Several of the segments were contributed by PGCA members

This might be helpful for those interested in facts rather than mythology
https://docs.google.com/document/d/1...hIiY62Hx4/edit

Unfortunately, the fate of about 30 barrels donated to 'Zircon' for metallurgical testing is unknown

To all who have responded to this post so far... Thank you. It has been opined that the finer crolle patterns caused by the twisting of the steel and iron billets results in a weaker barrel. What prompted the original question was, to what relative degree are the various patterns such as Chain..Bernard..American Flag etc. worked to achieve the desired design, or, would the ratio of the steel to iron composition be a deciding factor?

Austin:
1. Pattern welded barrels were fabricated with wrought iron and very low carbon steel

2. As a result of the process using high heat and pressure, it was the opinion of the metallurgist at METL that the resultant product became essentially a mono-metal.

20X photomicrograph after etching with 3% Nital solution showing the bands (alternees) and a crack probably within a steel alternee, but possibly at an iron-steel interface.
The parallel lines inferiorly may be related to shear forces during the rolling and hammer welding manufacturing process.
The globular inclusions are predominantly within the grey etched steel alternees.

https://photos.smugmug.com/Barrel-Ev...ck%2020X-L.jpg

The non-metallic inclusions are composed predominantly of silicon, phosphorus, and sulfur. Obviously, the 'cleaner' the iron and steel, the stronger.

3. The pattern is a result of how the lopin is 'stacked' and the rod twisted

Top: Star or Etoile’
Left: Double 81 Bernard
Middle: Extra-Fine Crolle
Right: Washington or "American Flag"

https://photos.smugmug.com/Damascus/...Meth%202-S.jpg

4. IMHO the pattern does not determine the strength of the tube. BUT if someone would like to cut about 3" of the nice Bernard II barrel on a C grade :crying: I'll run it over to METL for tensile testing ;)

Wernher von Braun “One test result is worth one thousand expert opinions.”

As a layman who has made a bit of this stuff, Id say that the metalurgists sound right. The time at welding heat results in carbon migration from steel to iron, possibly other elements as well. That said, if the metal was completely uniform it wouldnt likely etch differently.

It is true that the the twisting process can lead to small tears in the welded ribbands but its my opinion that most of these are re -welded during the spiral barrel welding sequence. The tighter the twist (finer pattern) higher incidence of tearing but also greater homogeneity of the finished product. In a well made barrel, the twists likely didnt result in tearing and the welds are all perfect. This is where the skilled workers made it happen.
Wrought iron is non homogenous and what most inclusions that began in the metal would remain, somewhat refined in size by the process. As Drew has said, higher grades are more refined prior to use in the barrel forging.

Sorry, duplicate of one of Drew's links.