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Change of plans. Decided to take another barrel donated by a fella here, with the previously posted bulges



Might be very interesting to compare radiography of normal barrel with the bulge section. AND have another Chain Damascus with a bulge on the way
I do expect (eventually) to have a barrel with a defect identified by MPI or radiography that can then be sectioned for analysis and microphotographs.

We routinely employ radiography at work and it is quite expensive. How much money have you sunk into this project so far?
If you do come up with a way to test intact Damascus barrels and reliably determine their integrity and safety, that would be a landmark contribution.

Virginian: I'll tell you in about 5 hours Meeting TEAM this am.
Please see http://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=357346#Post357346

Another VERY informative meeting with the lab manager and two of the NDT techs at TEAM. They also agree that radiography will be a better test to identify defects within the barrel wall, and can do elliptical views to isolate the wall (amazing!)
We are going to start with MPI, then will x-ray any abnormalities seen by MPI, then x-ray normal barrel, then x-ray the bulge, and generate images for publication of everything.

One of the techs was so excited that he headed back to the lab to start even before I was out the door

I believe we are going to end up with a cascade of complementary evaluation options based on one�s toleration of uncertainty, and bank account :
1. External visual inspection
2. Internal visual inspection augmented by direct or digital images the length of the bore
3. Chamber length, forcing cone length, and bore measurements for evidence of alteration from the original
4. Wall thickness measurements from breech to muzzle
5. Non-destructive Testing (NDT); likely radiography
6. Proof testing to at least 1 1/2 times the psi of the shooter�s intended load

Anything else?

Drew,

I don't ever recall seeing a basic strength of materials analysis of damascus - e.g., things like tensile strength, toughness, break load.

While this would be a sample of one, it would be really interesting to see how the properties of damascus compare to common homogenius barrel steels.

This analysis would be different from the analysis of the barrel failure that oriignally prompted this inquiry, but I think would be interesting nonetheless. It sounds like you are working with the guys who could provide this pretty quickly assuming you could give them samples of the right dimensions.

Good luck,

Ken

Thank you Ken. A tech at METL was breaking bolts when I visited. The one barrel that I have which is a candidate for destructive testing is pitted and over-honed Damascus-Twist, but the chamber might be a candidate for testing.
I did find these references to Whitworth, Krupp, and Seimens steel, but need someone smarter to tell me what it all means, and how they compare to 4140.

http://books.google.com/books?id=ycUOAAAAYAAJ&pg=PA614&lpg

http://books.google.com/books?id=czsyAQA...p;q&f=false

Drew, thanks again for your great work and research.

I'm sure there are enough people here, and I am included, that would help donate money to this great cause. If it is ok with Dave to do this, then you cant set up where the money could be sent.

While all barrels including Damascus would be of a different analysis, it should be close enough using what you have being tested.

Here you go David, and thanks
http://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=357346#Post357346

Possibly the Xray findings may validate the use of one of the surface dye tests, or some simple screening to decide if a more extensive look is needed for a set of barrels. Thanks for the updates Doc Drew.