How to blowup your rifle

[Timeout]

In the bike world we call that a JRA. As in, I was just riding along and this wheel I bought from you just folded in half. People think they are being clever and going to get something for nothing, but the willingness to help someone out goes away pretty quick when they start playing that game.

Reminds me of way back in my early days at the Chevy garage. Tow truck drags a 396 Chevelle in with a rod hanging out the side of the block. His story was "just idling around the East side of the square about 10mph and it quit running". The kid's dad may have swallowed that story, but he'd be the only one.

 

[Bowfishn]

When you get older your just happy when all your pee come out and at the right time when you want it to.

 

[RogerPA]

Looks like low temperature embrittlement to me. It broke at the receiver which does not get much heat from each firing and cools down quickly. Pronounced embrittlement occurs at -40F but is still a factor at -15F. Barrels and receivers are cold worked in the first place to make them hard but this also makes the steel brittle. Low temperature embrittlement does not affect the ultimate strength of steel but makes it susceptible shock loading, like igniting 86.8 grains of Retumbo behind a 230 grain bullet. Look it up "Low Temperature Embrittlement."

Well, I've learned a lot more in the last couple of hours about "Low Temperature Embrittlement" than I'd have ever guessed I'd know! There's even reference to it, as it relates to stainless steel rifle barrels, on the Alaska Outdoors hunting forum. Thank you for sharing.

 

[Steyr Luxus]

You say everything was tried. No I did not read all 22 posts. In aero space industry a heat / freeze cycle is used to install and or removed various components. so in my opinion the bolt should have been cooled and the chamber barrel should have ben heated (i.e. bolt contracts due to cold and barrel/chamber expands due to heating). Dry ice being the cooling component and a heat gun being the heating factor.
I would therefore ask your gunsmith if he tried this trick?

 

[GelatinousPig]

Is that a crack at the base of the neck on the brass, or carbon?

 

[bigngreen]

Let's get some fact posted, high pressure case measures .506 in the extractor groove, new case .463.
Case rim of high pressure case .550, new is .530.
Base of high pressure case that extends into the bolt nose recess measures .567, new case .545.
Case length of high pressure case is 2.846, new case measures 2.844.

This is a number picture of extreme pressure, this is the highest pressure case I've seen.
I was able to remove the receiver and both it and the bolt show pressure signs, the barrel shank is swelled.
I've just started looking at the barrel.

 

[500000KV]

I'm learning a lot on this thread. Thank you to the contributors.
Sounds like the owner should go buy a lottery ticket, very lucky. Glad he didn't get seriously injured.

 

[Lefty7mmstw]

Let's get some fact posted, high pressure case measures .506 in the extractor groove, new case .463.
Case rim of high pressure case .550, new is .530.
Base of high pressure case that extends into the bolt nose recess measures .567, new case .545.
Case length of high pressure case is 2.846, new case measures 2.844.

This is a number picture of extreme pressure, this is the highest pressure case I've seen.
I was able to remove the receiver and both it and the bolt show pressure signs, the barrel shank is swelled.
I've just started looking at the barrel.

It wasn't an over-length case then... A remmy chamber is usually a bit generous so I wouldn't expect that to happen unless you are 3.560"-3.580" or more...
If the bbl. was swelling already, she was just about ready to let go; the o.p. is seriously lucky...

 

[Timeout]

Let's get some fact posted, high pressure case measures .506 in the extractor groove, new case .463.
Case rim of high pressure case .550, new is .530.
Base of high pressure case that extends into the bolt nose recess measures .567, new case .545.
Case length of high pressure case is 2.846, new case measures 2.844.

This is a number picture of extreme pressure, this is the highest pressure case I've seen.
I was able to remove the receiver and both it and the bolt show pressure signs, the barrel shank is swelled.
I've just started looking at the barrel.

Thanks for the update. Those are definitely some radical expansion numbers. Would it be possible for you to obtain some of the cartridge cases that were fired immediately prior to the stuck case and measure those?

 

[Timeout]

It wasn't an over-length case then... A remmy chamber is usually a bit generous so I wouldn't expect that to happen unless you are 3.560"-3.580" or more...
If the bbl. was swelling already, she was just about ready to let go; the o.p. is seriously lucky...

The OP was for sure extremely lucky. Regarding the overall case length I have a question. I haven't ever measured any cartridge cases after they had expanded to this extreme. What I have done is measure cases that had been trimmed to length and then full length resized, without "bumping" the shoulder. Those cases OAL grew a couple thousandths rather than becoming shorter. That begs the question when a case stretches .020" down by the web, does the OAL actually shorten? I'M hoping that someone has experienced this and can provide factual information.

 

[J E Custom]

Let's get some fact posted, high pressure case measures .506 in the extractor groove, new case .463.
Case rim of high pressure case .550, new is .530.
Base of high pressure case that extends into the bolt nose recess measures .567, new case .545.
Case length of high pressure case is 2.846, new case measures 2.844.

This is a number picture of extreme pressure, this is the highest pressure case I've seen.
I was able to remove the receiver and both it and the bolt show pressure signs, the barrel shank is swelled.
I've just started looking at the barrel.

Looks like you have it well in hand. Looking forward to your final diagnosis.
This is the correct way to diagnosis a problem. One step at a time.

Thanks, BG

J E CUSTOM

 

[cape cove]

Good on you BG for doing this.Lots to learn for all of us.

 

[Pdvdh]

You can not buy it all you want, I wouldn't have thought of it either till I watched it happen with ammo that was long proven and not max loads. It's certainly a possibility, won't know if it's the cause till it's bore scoped and cleaned, then a chamber cast and bore slugging and that's about all the barrel will tell you. It could be the key bit of evidence went down the barrel and the bore will be lightly fouled and normal at least by looking at where the evidence leads during a root failure analysis a guy can learn something and either not repeat it or change his loading practice to make it more secure.

I've never seen a copper related pressure issue on a newer barrel, all were bores that we're getting rough. 6.5 Sherman, 300 RUM and a 7 STW. Very significant cleaning brought two back and the STW was rebarreled.

Is anyone aware of any smokeless powder rifle manufacturer or ammunition manufacturer that includes a cautionary statement on their product(s) that to ensure gun user safety, the barrel must be cleaned before shooting any new/different bullet from what had previously been fired?

 

[J E Custom]

Is anyone aware of any smokeless powder rifle manufacturer or ammunition manufacturer that includes a cautionary statement on their product(s) that to ensure gun user safety, the barrel must be cleaned before shooting any new/different bullet from what had previously been fired?

I have never seen anything like that my self and have never encountered this kind of pressure (Probably just luck) because for a long time I have avoided loads with pressures over 63.000 and don't exceed 65,000 under any circumstance.

J E CUUSTOM