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Brewster11
PostPosted: Mon May 06, 2019 10:34 am  Reply with quote



Joined: 08 Feb 2009
Posts: 599
Location: Western WA

This came in from the 16 ga yahoo group :

For those of you not active on Doublegunshop.com, here is a link to a thread concerning a chamber burst on a 16 ga, Elise during the recent Southern SxS shoot. The shooter was firing 16 ga, Herter factory shells. The root cause is not known yet, but most suspect an obstruction ahead of the chamber. The chambers may have been lengthened causing a weakness in them, but that is just speculation at this point. At a minimum it is a reminder to each of us that firing factory shells in our older guns comes with risk. Russ

http://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=545067&page=1
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Posted by: rwgray76@yahoo.com






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Pine Creek/Dave
PostPosted: Mon May 06, 2019 11:29 am  Reply with quote



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Brewester11,

Do you have the specification of the Herters shells he was using in his L.C. Smith gun, 2 1/2 or 2 3/4 at what pressure and what FPS? It would be nice to know what he was really shooting.

Pine Creek/Dave
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MSM2019
PostPosted: Mon May 06, 2019 11:52 am  Reply with quote



Joined: 04 Mar 2019
Posts: 71

If you start looking at the fractures against the rib, those are not new. This has nothing to do with high pressure-bad ammo-obstructed bore. That shotgun looks like it has tool marks in the chamber as well as some deep pitting. All lead to stress fractures and failure.

That fracture from the deep pit to the breech has been there for awhile.

If you look at the breech end....how long has it been since that shotgun was cleaned? Those carbon deposits are older than I am.

This is a case of poor workmanship and poor maintenance.

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WyoChukar
PostPosted: Mon May 06, 2019 1:36 pm  Reply with quote



Joined: 16 Jul 2015
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Location: Hudson,Wy

From what I am observing so far from the photos in the supplied link, this had nothing to do with chamber alteration unless the reamer worked off center, especially if held parallel, under considerable force. This degree of error would require securing the barrels in a rigidly supported fixture on a lathe. It's possible, if one is working "impaired/ well oiled" with little attention to detail; good cause to find a smith you trust.

That thin spot in the chamber is scary and if indeed came from the factory that way, it's amazing it ever left the launch pad so to speak. From what is reported so far, the case heads of previously fired rounds appear normal. A seriously out of round chamber should be visible in the form of deformed and possibly cracked case heads. Right now it appears that gun was living on borrowed time.

Obstruction? A good possibility with the bulge, but I'll wait for a verdict.

Thoughts on chamber length and cone work. That would have resulted in failure further from the breech, in the cone area. Second, the mid chamber wedge joint is still the thinnest spot with this barrel and pressure caused failure will occur at the thinnest/ weakest point. Third, the pressure at mid chamber is much higher than at the forcing cone, so even if both areas were equally thin, mid chamber is still the fail point.

Corrosion/ pitting? Won't say with absolute certainty, but there is discoloration at the epicenter of the failure.

Eventually we will see what Drew posts from analysis and inspection. Hopefully, there will be conclusive data.

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WyoChukar
PostPosted: Mon May 06, 2019 1:43 pm  Reply with quote



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MSM, your comments about tooling marks brings up a thought that few ponder: stress risers. Grooves and ridges do serve as stress risers, focusing transferred forces instead of evenly distributing them. That said, the single greatest stress riser in any shotgun barrel is the junction of the chamber to the base of the forcing cone. This channels stress and is also thin spot, even an abrupt thin spot if the cones are short/steep. Perhaps I will draw up some diagrams to post later, since these forces are often overlooked.

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MSM2019
PostPosted: Mon May 06, 2019 3:24 pm  Reply with quote



Joined: 04 Mar 2019
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WYO,

Your thoughts about the maximum pressure are right on the money. That nasty looking pitted spot is not too far from where a transducer is mounted in a test barrel.

The tool marks alone are not probably enough to cause a failure in a perfect chamber. This is obviously not a perfect chamber.

I do not think that forcing cone lengthening had anything to do with this failure. As there is no signs of failure at the forcing cone. The metal is nice and cleanly fractured except near the rib where it is thin. When metal fractures instantly it looks like side opposite the rib. When it has been fractured or fracturing over a period of time it becomes dirty and oxidized just like the fracture along the rib.

The failure starts at that nasty looking pit and runs back to the breech. When the barrel finally failed at the breech it allowed the chunk of chamber wall to be blown clear.

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WyoChukar
PostPosted: Mon May 06, 2019 6:10 pm  Reply with quote



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I know that they were not able to find the missing chunk of barrel, but it was observed hitting a nearby tree. It seems that a metal detector might allow it to be located.

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WyoChukar
PostPosted: Mon May 06, 2019 6:16 pm  Reply with quote



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Herter's specs? From what I read, it was a factory shell. 2 3/4" Select Field Dove and Quail load, 2 1/2 dram, 1 oz. of lead @ 1165 fps.

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Pine Creek/Dave
PostPosted: Mon May 06, 2019 6:29 pm  Reply with quote



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WyoChukar,

With that light Herters load, I am betting on some kind of obstruction.

Pine Creek/Dave
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MSM2019
PostPosted: Mon May 06, 2019 7:31 pm  Reply with quote



Joined: 04 Mar 2019
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When you have an obstruction, there will be a bulge in the barrel.

Look close, where is the bulge?

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fourtown
PostPosted: Mon May 06, 2019 8:06 pm  Reply with quote



Joined: 25 Jan 2014
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After reading a couple of pages of the discussion about the burst barrel in that link, I quickly remembered why 16ga,com is the only gun forum that I follow.
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Brewster11
PostPosted: Mon May 06, 2019 9:28 pm  Reply with quote



Joined: 08 Feb 2009
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Location: Western WA

Quote:
Do you have the specification of the Herters shells he was using in his L.C. Smith gun, 2 1/2 or 2 3/4 at what pressure and what FPS? It would be nice to know what he was really shooting.


Dave, based on inspection of the photo of the hull and comparison to my various Herters empties it was 2 3/4" low brass 1165 fps. I don't recall the published PSI for that load.

B.
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fn16ga
PostPosted: Tue May 07, 2019 2:59 am  Reply with quote
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I had Tom Armburst test some Factory Herters 1oz #8s a couple years back Fps right around 1200 , psi right at 11500 .
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tramroad28
PostPosted: Tue May 07, 2019 3:46 am  Reply with quote



Joined: 20 Jul 2011
Posts: 478

The appeal of Herter's shotshells was price not pressure.

A mix of helpers is most often somewhere within the origination of every issue.

I hope the hands-on folks discover the greatest helper and folks learn.....luck may not side the next guy or gal.
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sneem
PostPosted: Tue May 07, 2019 3:11 pm  Reply with quote



Joined: 19 Apr 2008
Posts: 453

Looks to me like long time corrosion between the barrel and rib right at the fracture.

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