doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com The Southern Chamber Burst Gun

Stan, the Army originally trained me as a Combat Engineer. Specifically, a Combat Demolition Specialist. But that was over 50 years ago, and I had to dredge up very old memories and then confirm them with a bit of research (and a big hint from Miller when he used the term "deflagration"). Because ammunition doesn't use a high explosive as a propellant--which is a very good thing for all of us!--it never really detonates. But used in ways it was never intended to be used--like in a pipe bomb--smokeless powder will certainly explode. That term applies accurately to powder just as much as it does to TNT, dynamite, C-4, Composition B, etc--all of which have explosive properties. We don't normally talk about an explosion in reference to ammunition fired in a gun, but in fact--smokeless powder being a low explosive--that would be a more accurate term than detonation, which is a term that differentiates high explosives from low explosives.

But I doubt we're going to end up using English more accurately regarding ammunition, because we've all been using it inaccurately for far too long.

I respect your constant diligence to use the correct terminology, Miller, but in today's world you may be tilting at windmills. It simply doesn't bother me when a word or phrase has taken on "a life of it's own", and the rest of the world completely understands the intended meaning of it.

While were at it, tho' ............ I imagine you don't much like the word "detonation" used in this regard, either. Gasoline doesn't really explode either, does it? it burns. If it actually did detonate, I expect it would blow the engine, as you say, to "smithereens". But, the most highly technical researchers and test labs use the word to describe this phenomenon that takes place inside the combustion chamber of an internal combustion engine.

https://www.enginelogics.com/engine-detonation/

All my best, SRH

I assume the shells used will be tested for pressure.

Here is another idea for consideration. When the barrels were assembled into a bundle for brazing together, the barrels had "flats" filed on the sides, where they came into contact with the top and bottom wedges/rib extensions. When a close fit was achieved, everything was cleaned and wired together with flux and brazing material in the joints. Then they were heated until the brazing material flows. Sometimes the bundles were heated until they "glowed". If one of the flats on a barrel was filed too thin, itself a problem, the too thin section would be more likely to "burn" in heating the bundle. After assembly, this couldn't be seen by an inspector and if it passed proof, it would be passed to the public. One proof load doesn't always show a defect, sometimes it takes repeated "shocks". Rechambering the gun is not what caused the incident.
Mike

Thank you Mike, and good thinking.

Yes, I will receive some unfired shells from the same box and intend to send them for ballistic testing.

ed: I don't have the barrels yet.

re: the missing chunk. This is the blown out segment from the 2014 study



It would seem obvious that actually measuring the wall thickness of the edges, esp. the medial formerly brazed edge (numbers are good; eyes fool us) might be of worth. And preparation of the edges for photomicrographs by the metallurgical engineer at METL is much easier using the chunk than cutting up the remains of the barrel.

Arrogance is a dangerous thing. One tends to make a presumptive diagnosis, then seek data to confirm that presumption, and discount or ignore data contrary to that presumption. In medicine, it gets patients killed BTW.

And since William seems intent on turning this (once again) thread into his personal toddler wading pool of filth and an opportunity to continue our feud, and since it is my time and money, of which I have, I'll choose to do what it takes to arrive at a reasonable conclusion as to the cause of the blow-out, and just maybe we can learn something. What a concept!

This might be helpful. A 1906 00 12g and the rib extension braze line is quite apparent. The hook line is more difficult to see in the image, but apparent visually



Clearly the superior-medial barrel that was ground flat is much thinner, but again, because of the strength of the (correctly performed) braze, the "wall thickness" includes the wedge.

The key words being "correctly performed". I have my doubts.

I think that the gun managed for so many years would seem to indicate that the braze connection was within an acceptable range, which would include the temperature to perform the braze. I don't think these incidents are design or execution problems, but more likely exceeding an intended limit or changes that had subsequently happened.

Perhaps it was simply metal fatigue. Higher pressure modern ammo, causing imperceptable expansion and retraction on each shot, exacerbated by the failure point (dark spot). 100 years and thousands of iterations, she finally let go. (^contraction)

If that is the scenario, the Energy Dispersive X-ray (EDX) scanning photomicrograph of the fracture edge would look something like this: from left to right low cycle ductile fatigue "waves in the sand" or "beach marks", then plastic deformation (stretching) "fish eyes", and then terminal cleavage



If an extreme pressure over-load burst there would be no "waves in the sand"