Thin wall thickness

[DoubleOframe]

Recently we picked up all of the double gun parts from Bachelders when they closed and one set of barrels in the lot was an 0 frame, 20ga GH with a blown tube. Measured with calipers and a wall thickness gauge and it was only about .010"-.012" at the blowout.

The opposite tube was .032" in the same spot and both bores measured .622" so I don't believe the blown barrel was back bored. This set will go on display in our front showroom as a good reminder to check the wall thickness whenever possible!
















Measurement above the blowout


Opposite tube measured about .032"

[mobirdhunter]

Channing, thanks for posting this. It may help someone avoid an accident.

[Dean Romig]

It is possible that a certain amount of stress induced stretching may have occurred immediately before the failure…





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[DoubleOframe]

Originally Posted by Dean Romig

It is possible that a certain amount of stress induced stretching may have occurred immediately before the failure…





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Dean,

I wondered that as well, possibly there was a bulge there but above and below the blowout also measured very thin as shown in the photos. The blowout was centered at 13.5" inches on a set of 26" barrels.

[Drew Hause]

Thank you Channing.
re: the effect of bulging prior to the burst on wall thickness. I discussed the issue with the Metallurgical Engineer doing one of my failure evaluations. His answer was "not much".

Helpful demonstration.
The straight ribband end welds are marked.
The crack clearly occurred at the rod to rod weld.
The terminal cleavage/split was across the welds.
Damascus mythology has been that barrels will "unwind like a slinky". Not if the ribband welds are intact.

[Dean Romig]

And we have seen pictures of Damascus barrel failures that actually appear to have fractured in a more crystalline separation as opposed to the stretching and splitting of fluid steel barrel failures.





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