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02-24-2014, 11:24 AM | #63 | ||||||
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Drew: Are you having the barrels radiographed to look for cracks, etc. ? How obvious is a crack in the barrel on these radiograph films ? Reason I ask is this: I had my ca. 1886 hammer gun radiographed, and although they stated there was a "linear defect" - I'd challenge anyone to see it on the film. My dilemma was that my naked eyes saw what looked like a partial circumfrential crack (as if it was following the weld lines in my twist barrel), but the radiograph flim didn't seem to show much at all... How can eyes be more telling than an X-ray ? (I should probably just send the barrels to Brad !)
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02-24-2014, 12:37 PM | #64 | ||||||
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John: I believe (hope) that radiography is the best non-destructive means to assess what is happening within the barrel wall; inclusions, voids, weld failures, non-weld cracks. Just as with an MRI of any body part, interpretation of course requires an expert and experienced human eye. No one at TEAM has x-rayed Damascus barrels, but they have lots of experience in industrial applications of radiography.
I would very much suggest that a 'linear defect' seen on radiography is real, and really a crack, and really an indication that the barrel is unusable. Of course, sectioning the barrel for photomicrographs would confirm the diagnosis if you would like to donate the barrel to science Unfortunately, the two barrels I've had x-rayed so far show only what is very likely to be pits on (not within) the bore wall; defects that are not linear and can be correlated to the findings on visual exam of the bore Negative image - defects grey/black. The white stuff is felt to be porosity in the solder I'm meeting with the techs at TEAM again in the am and should have more images thereafter, and another barrel is arriving today with an apparent crack visible on the outside of one barrel. SO I will have at least three more barrels to x-ray for the data base (total of 5). One thing clearly shown is that the mythology that pattern welded barrel walls are 'a mass of welds, voids, inclusions, slag, etc.' is wrong. We'll have more evidence when the photomicrographs are done on the barrel blow out analysis.
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http://sites.google.com/a/damascuskn...e.com/www/home Last edited by Drew Hause; 02-24-2014 at 01:05 PM.. |
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02-24-2014, 01:21 PM | #65 | ||||||
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My radiograph wasn't as "nice" as that one (it appeared to be darker, overall). In some areas (my radiograph), it did look like you could see the twist pattern, so I can see where the "mass of welds" crowd may have formed that opinion. What still stuns me is that you can PLAINLY see my "defect" with your eyes when you look down the barrel. (Plus, you can get a dental pick to "grab" the defect, too.) With all of that "low tech" evidence, if it still only shows up (on an X-ray) as a faint line that only the most acute & trained eyes can see, I have little faith in it being able to catch cracks that aren't so obvious. But obviously, it's the best method available, short of a destructive test...
Don't mind me - I'm just bummed out that the only gun that ever fit me perfectly has a cracked barrel. Thanks - take care ! |
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02-24-2014, 02:12 PM | #66 | ||||||
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OUCH!! David, glad to hear you're OK!! I saw the same thing happen here at our range about 4 years ago. The shooter was using low pressure factory shells made specifically for vintage guns. The gun let go, left barrel, right at the leading edge of the chamber. Nobody was hurt but the shooter had some powder burns (very minor) on the left side of his face. Another member of our squad had a small piece of shrapnel hit his forearm and stick there. Sadly the barrels were ruined, happily the squad was fine.
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