Blew up a gun Thursday... now tell me WHY?

[swheeler]

Did you feel any type of delay or hang fire when it happened?

I would like to know that too, first shot any, second shot any?

[jonk]

To answer a few of the questions posed:
1. FA brass. Not sure of the year as the case was destroyed, but that lot was OLD- from the 20s through the 40s. I have hundreds of these, never had an issue. I got it 'new' with original primers (in and of itself interesting) and cut some down to 8mm, and turned the necks. I have never annealed it. I admit to not knowing how many times I have fired it, as I don't keep track with cast loads; I've never felt I needed to. I'd guess around 10 firings. The brass had no cracks- I inspect each before loading- and had no sign of a stretch ring around the web area just forward of the head. Still, I may now scrap it or use it only for cat sneeze loads.

2. Headspace was not an issue. These rounds were made from brass previously fired in that gun and neck sized only with the Lee Collet set. I check all brass with a caliper before each loading. This stuff was in spec.

3. This was the first batch I loaded that day. While I suppose that some faster powder could have been in the measure from previously, I don't as a rule leave powder in the measure. I haven't yet torn down the other rounds, but surely will and if that's the answer, shame on me and I will post it. That's assuming there was enough in the measure to show up in other cartridges and not just a smidge left for one. I kind of HOPE that IS the answer, as it would assure me to the safety of the powder itself. The powder shows no signs of deterioration visibly or by smell. Still, depending on what that powder might have been, it may not be visually evident- it would have to be something suitably different from the 867 to identify. If it was something like 2400 or BLC2, I probably won't be able to see it. But just for argument, if there WAS some in the measure from my last loading session- say 2400 which I use a lot of- a case full of THAT to the neck surely WOULD have done this sort of thing!

One line of reasoning against this thinking is I had to adjust the dispenser and throw several rounds to check on a scale to get it dialed in. If there had been some other powder in there, it would have come out first, and either I would have noticed it, or at least it would have been returned to the TOP of the powder hopper, meaning by the time I got to loading only the proper powder would have been flowing through. I did not empty the hopper during this session and had to pour 1/3 of it back into the jug. So it would have had to have had a LOT of the wrong powder in the reservoir for me to do this, and I've now ruined the whole batch if this happened. I will surely look when I pull the rounds though.

4. It is possible that some unburnt mummies got in the chamber causing a tight neck, but it would have to have been a lot; when I have that happen I usually feel it on closing the bolt. I didn't here.

5. No hang fire or delay at all, neither on the first shot nor on the second.

6. The barrel isn't bulged. Whether the chamber is rung will have to wait until I get the case out. It's soaking in Kroil now and I plan on filling the case with Cerrosafe and tapping it out. I CAN see that the case head is separated, though given the lug set back that isn't surprising.

[Finster101]

Glad you are okay. We all would like to find the cause as I'm sure that you REALLY would. Thanks for posting up. I'm not much help as to what may have caused it, just trying to follow along and learn something.

James

[swheeler]

To answer a few of the questions posed:
1. FA brass. Not sure of the year as the case was destroyed, but that lot was OLD- from the 20s through the 40s. I have hundreds of these, never had an issue. I got it 'new' with original primers (in and of itself interesting) and cut some down to 8mm, and turned the necks. I have never annealed it. I admit to not knowing how many times I have fired it, as I don't keep track with cast loads; I've never felt I needed to. I'd guess around 10 firings. The brass had no cracks- I inspect each before loading- and had no sign of a stretch ring around the web area just forward of the head. Still, I may now scrap it or use it only for cat sneeze loads.

2. Headspace was not an issue. These rounds were made from brass previously fired in that gun and neck sized only with the Lee Collet set. I check all brass with a caliper before each loading. This stuff was in spec.

3. This was the first batch I loaded that day. While I suppose that some faster powder could have been in the measure from previously, I don't as a rule leave powder in the measure. I haven't yet torn down the other rounds, but surely will and if that's the answer, shame on me and I will post it. That's assuming there was enough in the measure to show up in other cartridges and not just a smidge left for one. I kind of HOPE that IS the answer, as it would assure me to the safety of the powder itself. The powder shows no signs of deterioration visibly or by smell. Still, depending on what that powder might have been, it may not be visually evident- it would have to be something suitably different from the 867 to identify. If it was something like 2400 or BLC2, I probably won't be able to see it. But just for argument, if there WAS some in the measure from my last loading session- say 2400 which I use a lot of- a case full of THAT to the neck surely WOULD have done this sort of thing!

One line of reasoning against this thinking is I had to adjust the dispenser and throw several rounds to check on a scale to get it dialed in. If there had been some other powder in there, it would have come out first, and either I would have noticed it, or at least it would have been returned to the TOP of the powder hopper, meaning by the time I got to loading only the proper powder would have been flowing through. I did not empty the hopper during this session and had to pour 1/3 of it back into the jug. So it would have had to have had a LOT of the wrong powder in the reservoir for me to do this, and I've now ruined the whole batch if this happened. I will surely look when I pull the rounds though.

4. It is possible that some unburnt mummies got in the chamber causing a tight neck, but it would have to have been a lot; when I have that happen I usually feel it on closing the bolt. I didn't here.5. No hang fire or delay at all, neither on the first shot nor on the second.

6. The barrel isn't bulged. Whether the chamber is rung will have to wait until I get the case out. It's soaking in Kroil now and I plan on filling the case with Cerrosafe and tapping it out. I CAN see that the case head is separated, though given the lug set back that isn't surprising.

Jonk I was thinking unburned powder from inside the case(the load) was pushed forward on ignition and wedged between the inside of the neck and the bullet, unable to release the bullet. Glad you are OK! Got a flinch now?

[Larry Gibson]

Normally if it is barrel obstructing there is a bulge in the barrel.

Only if a bullet is lodged in the barrel and another bullet is fired behind it. In the case of SEE the original bullet becomes a momentary bore obstruction and pressure rise too fast befor the bullet starts moving again.

What Jonk had was a classic SEE.

Way too slow burning a powder even if the case was full.

Heavy bullet.

Long throat.

Two previous shots fired whch left the long throat fouled and probably gritty from poor combustion.

Magnum primer which blew the bullet forward into the gritty throat where it stuck because the pressure of the burning powder had not bult enough to keep the bullet moving.

Psi reaches a point where the powder burns efficiently and rapidly before the bullet can start moving again.

Psi exceeds structural limit of the case used and gas excapes into receiver causing damage.

Yup, that's a classic SEE alright.

Larry Gibson

[HollowPoint]

I've been there and done that; and for the life of me, I still don't know what caused that incident.

I only know that since that time I've been accused of all manner of things leading up to that event.

I'm glad to hear you're OK. And in a strange sort of way, I'm glad to know I'm not the only one who's experienced such and thing.

You'll find that in some ways, dealing with the aftermath can be as confusing and difficult as dealing with the incident itself.

HollowPoint

[BruceB]

Your excellent photos indicate clear similarities between your blow-up and one that destroyed my wife's Browning Safari rifle (FN Mauser) many years ago. Based on relative destruction at various locations, hers generated even more pressure!

The incident pre-dated computers and digital cameras, so no pics unfortunately. However, I wrote a decent description of the damage which can be seen by searching for "karen moose" The actual thread title is "The Day Karen Met The Moose".

I'm glad you escaped injury. My wife wasn't quite so lucky.

[H110]

I then go to a new load- awhile back I got 2 jugs of surplus cannon powder from wideners, 1 jug of 872 and 1 of 867.

Outside of some error in the loading process on you part this is the problem, this the only thing that changed. Pull the boolits from the remainder that were loaded and check charge weights as well as case dimensions, that's where I would start. I don't know that you will ever determine the actual cause but it is a pretty safe bet the powder is to blame, either TOO SLOW or faulty in some way.

110

[Dutchman]

Could you provide a couple photos of the outside of the receiver?

I'm amazed at the amount of lug setback and that the receiver ring didn't come apart. I think I have to respect the overall strength of the rifle in the first place. I wondered how much worse it would've been if there hadn't been a gas escape hole retrofitted to the rifle. That small hole isn't much but it obviously provided some small but significant amount of pressure relief to the overall "vessel" of the action. A little bit more pressure and most likely the receiver would've grenaded. Whether that would've resulted in the bolt coming back into the shooters eye/face or if the receiver grenading would've retarded the bolt from coming rearward with enough force to further injure the shooter.... we'll never know.

I think maybe LarryG's SEE theory may fit this situation closer than not.

I own one of these rifles. They are not a "Mauser". The only Mauser element is the magazine.

Dutch

[Larry Gibson]

I want to take this opportunity to caution about using powders with inappropriate burning rates and ignition charactoristics in non suitable cartridges just because we "have this jug of powder" and we want to use it up or simply because the powder is cheap. How many time do we hear something like this as a thread starter; I have this jug of 2400 that I want to use up in my 32 ACP. I can find any data for it. Anyone got a good load?

Yes that may be an extreme case but it is meant to give you the idea. Consider there probably isn't any load data because the powder isn't appropriate for the cartridge. Now I'll be the first to admit to experimentation. However, I correlate with other data and always take ignitability of the powder as a serious consideration. I have made mistakes by not doing so and have learned from my mistakes. With the speed of the internet and forums like this there is no reason for others to repeat the mistakes.

Things I have learned to caution against;

Using too slow a burning powder for the cartridge.

Using a powder with poor ignition charactoristics for the load level used. Even the faster burning powders can fit this in some applications.

Using a filler with too fast a burning powder or with bottem end loads with too low a loading density.

Using top end loads without working up the load.

Trying to do advanced level loading and load development without any experience, particularly when based on advise from posts. While that advise can be good it is always minimal and not detailed enough as information found in manuals.

Just a few there but in this case with this thread the powders used were probably very inappropriate for that 8mm cartridge. All this is just my opinion of course but we SEE (pun intended) these very errors all to often and occasionaly, as in jonk's case, with catastrophic results.

This is not meant as a direct criticism of jonk BTW. I'm just stating the facts so we may learn. I've been in on the destruction of 2 rifles (many years past....I was a hard learner back then.....) from using too slow of burning powders.......

Larry Gibson

[nvbirdman]

Is anybody making a connection between surplus powders and false economy?

[Char-Gar]

A couple of more thoughts.

1. I still think SEE is the likely culprit as stated in my original post.
2. Many of us have used WC860 and WC872, but until today I never heard of 867, so I have no idea of how to load the stuff.
3. I noted you used a magnum primer, which make? Those of us who have been around this stuff, avoid Winchester Magnum primers like the plague for cast bullet loads.

Winchester LRMagnum primers have a very high "brisence", which means they release 100% of there energy quicker than any other primer. In any load, the primer starts the bullet before the powder charge ignites and the "big push" (as Phil Sharpe liked to say) takes over. With a high brisence primer (WLRM) the bullet can be shoved far enough down the barrel to stop for a nano second before hit by the main charge. The harder to light off the charge, the worse the issue can be.

I have not seem the mention of WLRM primers as a no-no in conjuction with cast bullet loads in several years on this site. But, it was common knowledge some years back. This is the price of not having some of the "wise ones" not around anymore.

The manufacturers change their primer formulations over time. A generation or two back, it was often recommended to use Remington 9.5 LR primers for cast bullet loads, because of their low brisence. I still use Remington 9.5 primers for all my cast bullet rifle shooting. I use them with WC872 and just take the unburned kernals of powder as just the price of good accuracy.

The difference in primers is not often understood, with them being called "hotter". There was even fellow a few years back and did some work on how far the primer itself would penetrate into soft wood. None of these deal with brisence issue. Brisence has nothing to do with the tempreture of the flame, or the amount of the flame, it is about the speed with which 100 percent of the energy is released.

When it comes to magnum primers and unknown god awful slow powder, this is likely the issue that caused the SEE.

[Bwana]

Is anybody making a connection between surplus powders and false economy?

I have burned around $1000.00 worth of "surplus" powders over the years. Don't blame the powders for the operators error.
I would also comment on the locking lug setback. Is it possible that this setback ocurred over a period of time during which loads exceeded the tensile strength of the locking lug seat area? Just because it was "discovered" after the blowup doesn't necessarily mean it happened then.
I am not convinced this was a SEE event.

[HangFireW8]

Is anybody making a connection between surplus powders and false economy?

Only when combined with improper application, in which case canister powders are equally dangerous.

I used to have some surplus 4895; I used it like 4895, and it was some of the finest powder I've ever used.

Those using 50 BMG or 20mm powder in battle rifle cartridges must accept that this is an experimental application and strange things may happen. I credit the original poster for being honest and sharing with us so that we all can learn.

I agree that this is probably SEE, but we cannot know for sure. The ordnance protocol for solving issues like this (or hang fire) is to sequester that lot and surrounding lots, do lots of test firing and try to figure out whether the issue is with that batch or the design. Also dissect charges, chem analysis, etc., etc.

We don't have all those luxuries but we can examine what we have. The fact is slow ball powders are more given to SEE than faster or stick powders. I don't experiment with them for that reason and another, if it takes twice as much very slow powder to do the job then at half the price it is no real bargain. That's the real false economy. I'll continue to buy surplus powder, but I use it for its intended application. I accept the risks are higher than canister powder, but lower than a stretched application.

Lets remember for decades the only 4895 or 4350 were surplus powders; now they are among the most trusted.

[HangFireW8]

A few more comments. Atomized brass doesn't necessarily mean overpressure. It might just be the result of gas cutting of a split case. Just like leading doesn't necessarily mean overpressure, just poor gas seal.

Lug setback can be the result of gas pushing against a larger area and being able to do more. For the technical reasoning behind this read Stuart Otteson's analysis of the large bolt Weatherby magnum action and why it wasn't such a great idea. This is counterintuitive to some of us, but the math, engineering and experiments back it up.

[DrB]

Normally if it is barrel obstructing there is a bulge in the barrel.

I certainly agree if it is much forward of the chamber... I am less sure if it is in close proximity to the chamber.

[madsenshooter]

Wasn't there a mention of faulty FA brass in Hatcher's book? I preparing to move, can't find it in the mess. I can't go along with the SEE theory. Only way I could see a lead bullet stopping hard enough to raise pressures to that extreme would be a rusty old throat such as one of my Krags had. Couldn't even push a patch through it.

[Larry Gibson]

I have burned around $1000.00 worth of "surplus" powders over the years. Don't blame the powders for the operators error..............I am not convinced this was a SEE event.

I've probably burned up more than that in surplus 4831, 4895 and BLC1 in years past. I still have 8+ lbs of surplus 4831 and 60+ lbs of surplus 4895.

I do concur the powder was not "bad" nor "at fault", was jonks use of the inappropriate powder for that cartridge that set the stage for the SEE. His choice of the magnum primer probably helped it along.

As to whether or not it was an SEE; all the conditions and criteria for a SEE are there.....the typical results of SEE are evident.......if it walks like a duck and quacks like a duck then it's probably a...........

Larry Gibson

[DrB]

My only problem with the suggestion of SEE is that it requires the assumption that an under charged case happened to occur on the second round, that an undercharged case was missed in a nominally FULLY charged case, and that SEE, which may or may not even occur with this powder/case/primer did in fact occur. Has anyone ever reported probable see with this particular powder?

An event with the second round seems a bit of a coincidence to me. Was the second round fired the second round loaded? Second to last? Unordered with respect to loading vs. firing? The nominal load was a case FULL. Were ANY incidents of under charging observed among ANY of the charges thrown (both observed and corrected OR upon disassembly?). Have you observed/corrected under charging with your setup with any frequency (or ever) with these powders?

If you have a history of undercharging, SEE becomes more plausible on just the second round fired, especially if anyone else has ever observed it with wc867. If no one has ever encountered it before, and there is no history to point to a likely undercharging, SEE becomes a possible but improbable theory.

Another question... is the assumption of a special cause such as SEE necessary? Given the dearth of load data out there for this cartridge and wc867, and the lack of a gradual load work up in this instance, does anyone KNOW that this particular charge, chamber, primer, and bullet doesn't nominally produce excess pressures? It wouldn't be conclusive, but it would be interesting to know what QL predicts, or even better mean and sd pressure profiles such as would be worked up by a serious load publisher.

It would be nice to conclusively discount the nominal gross over pressure scenario... as if it is what is expected to occur with this load it is likely to bite the next one of us who tries something very similar to the OP. Given the general discussion online about these powders and the apparent assumption that these powders can't be overloaded in cases smaller than 50 bmg, any of us who ignore the usual work up from known starting point rule may be in jeopardy if our assumption is mistaken.

So is the assumption well founded that wc867 + magnum primer can't develop excessive pressure in 8x57?

[HangFireW8]

Has anyone ever reported probable see with this particular powder?

An event with the second round seems a bit of a coincidence to me. Was the second round fired the second round loaded? Second to last? Unordered with respect to loading vs. firing? The nominal load was a case FULL. Were ANY incidents of under charging observed among ANY of the charges thrown (both observed and corrected OR upon disassembly?). Have you observed/corrected under charging with your setup with any frequency (or ever) with these powders?

While undercharging increases the possibility of SEE, it by no means is a mandatory prerequisite of SEE. At BRL we saw SEE (in admittedly larger guns) in different circumstances, including too much primer and not enough primer. SEE in its essence is an undersired transition of an energetic material from deflagration (burn rate) to detonation (explosion). Any number of circumstances can cause this transition.

What gets my attention is that the OP had just upped the load slightly and may have created a compressed load. Compressed loads of ball powder are slower to ignite, since there is not as much air space for the primer flame to propogate. They also create the possibility of primer induced debulleting, creating the dreaded start/stop/start motion of the bullet. Such a situation may not need to induce SEE to blow out rifle brass; a weak old case and a single instance of boolit stop/start may cause enough of a pressure excursion to create the damage done without an actual SEE event. (See my previous post on damage).

EDIT:
OK, on re-reading, I see that Jonk, the OP, has already posited the primer debulleting theory, as quoted below. I have to point out that not only SEE is a possibility in this circumstance, but so is a typical run of the mill pressure excursion, where pressures go above norms due to a more highly efficient burn.

I'm wondering if the mag primer didn't dislodge the bullet and stick it in the rifling, and in so doing blew the powder forward as a whole unit before the powder really started burning- but of course some HAD started burning, then the rest of the column caught and I got the SEE. In this line of thinking, I'm wondering if the bullet had already been just touching the rifling and not able to easily move, or if the throat had been more worn and the bullet had fully exited the case (I doubt it did if this happened) perhaps I wouldn't have had the issue.

?

HF