doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Blow Up Post-Mortem Part 2

I'll probably dribble out information as available, because I NEED YOUR HELP and you are very likely to think of something that should be done, that I did not.
Received the barrel with the empty shells in the chamber, the fragment, the empty shells that had been used, and 4 reloads.
1. I now know what a loose rib 'clunk' sounds like
2. The empties will be examined for missing components/parts
3. The reloads will be opened and the powder weighed.
4. Taking quality pics is very difficult, and I'll try again in the morning when the sun is not as intense.

First impressions
1. The rust shown on the previous pictures is clearly new
2. The chambers have not been messed with; 2 5/8" with a short forcing cone and only the expected tool marks. Wall measurements to follow but they appear adequate

3. The shell in the left chamber came out easily using a long dowel. I don't think the primer shows increase pressure and looked like the other



BUT extractor indentations were present in the steel case head. I may need pro help to get an adequate image, but look at line toward the bottom



4. The fragment was bent almost 90 degrees by the force



the crolle pattern is visible on the inside of the bore BUT NOT ON THE SHELL CASE as previously thought



Chamber and forcing cone inferiorly, barrel bore superiorly




In the morning I'll start measuring every bit of wall that I can get to, check for evidence of a bulge, and try for some more pics. Stay tuned.
I am meeting with the metallurgist at METL next Monday.

Measure the shot charge and of course identify the powder.

Thanks Drew.

Yes, thank you Drew.

Forgive me if I'm showing my ignorance, but if the shells in use were 2 3/4" Remington Gun Club reloads, I would suggest that the above statement should be filed under "Potential Contributing Factors".

I would suspect incorrect powder

Thanks Drew

Here is the load recipe from the Hodgdon site, which the shooter has been using for about 2 years
http://www.hodgdon.com/basic-manual-inquiry.html

Remington Gun Club hulls
1 oz. shot
Win 209 primers
WAA12SL replacement wads
17.5-gr Clays powder using #32 bushing in MEC 9000G

The recipe has 15.7-gr 7100-LUP, 1125 fps; 17.0-gr 8200-LUP, 1180 fps; 18.4-gr 9500-LUP 1235 fps

I'm surprised Hodgdon still reports LUP rather than piezo-electric transducer pressures, which are likely higher.


An unfired/loaded shell measures 2 5/16�
A fired shell 2 11/16�

Drew, it appears from the photo the primer is cratered from the firing pin. What do you see?

Also, you might measure the diameter of the hull's head--it sure appears to have stretched.

Do your pictures indicate a crystalline structure on the fourth picture at 1:00? If it is, it may be telling you something.

bill

I have seen a steel barrel gun that blew at the chamber with shells loaded on a 9000. Double charge was the admitted cause in that instance. With the auto advance with the 9000 it is easier to loose track and get a bloop with no powder and then a double charge. Just a thought. Mark