IN SUMMARY I'll start with a copy of the usual response from the ShotgunWorld Reloading Forum:
"A Damascus barrel is NOT as strong as steel barrel of the same thickness. Think about how a Damascus barrel is made, there are seams and voids all over it. If you don't believe me have a damascus barrel magnafluxed or x-rayed."
That was not the finding of the 1891 Birmingham Proof House Trial
Please review, and note that Whitworth, Siemens-Martin, and English “Superior Barrel Steel” were tested
http://docs.google.com/document/d/1dnRLZgcuHfx7uFOHvHCUGnGFiLiset-DTTEK8OtPYVA/edithttp://docs.google.com/a/damascusknowled...2Hx4/edit?pli=1 MagnaFlux or PD testing shows defect on the surface, not what is happening within metal.
The primary motivation in analyzing this barrel blow up is to apply modern testing, possibly including SEM, fully recognizing that one more than 100 year old barrel does not represent a statistically significant sample.
I will be meeting Monday with a Metallurgist at METL
http://metl.com/services/ to explore analysis options, and if anyone here is interest in something other than BS, they might keep an eye on the DoubleGun thread...or not if more comfortable with mythology
http://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=356377&page=1 I do appreciate the statements made here regarding the near impossibility of loading a double charge of powder without evidence thereof with visual inspection of the shell/crimp.
What can we say with
certainty:
1. The wall thickness of the chamber and barrel wall are adequate
What can we say with
confidence, but still only as an (educated)
opinion:
1. A powder overload was unlikely
2. The fracture/blow out did not occur along ribband weld lines
3. There is evidence of a bulge, and a bulge means an obstruction
As Mike shared (and thanks again)
Major Sir Gerald Burrard,
The Modern Shotgun, Volume III, p. 415:
"In the case of an obstructional burst the really essential evidence is the ring bulge. If there is a ring bulge, there must have been an obstruction; and the absence of a ring bulge is conclusive proof that there could not have been an obstruction."
4. The extractor indentation upon, and expansion of the steel shell head, can be explained by the pressure increase prior to barrel rupture
Anything else?And the prize goes to James Flynn who made the correct diagnosis back on Jan 27
Monday I will be discussing:
1. composition analysis to see if we can determine a modern equivalent to the iron and steel used in fabricating the barrel
2. the best procedure to evaluate the barrel wall for 'seams and voids', inclusions, and micro-fractures.
3. If there would be any value in PD testing.
4.
AND THE MOST IMPORTANT QUESTION - how may we best evaluate the integrity of our pattern welded barrels using non-destructive testing????
