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

[jonk]

UPDATE: Please see the new picture:


Well I said I was big enough to admit if I was at fault; one user suggested a contaminated powder dispenser. I really doubted this but was happy to investigate. I got around to pulling the remaining loaded rounds today; look what I found in one.... circled in red is the obvious difference between what I believe was 2400 on the left and WC867 on the right. Notice the chopped, flat appearance of the 2400 flake vs the globular round appearance of the 867. How I missed this is beyond me; I do not leave powder in the hopper, but apparently I did this time! I found one round with 2400, one with a mix, and the rest were 'normal.' Of course, now I have to consider what to do with the powder. I don't trust just pouring it out as up to 150 gr of 2400 might have been returned to the 8lb jug while I was dialing in my charge. I suppose I COULD carefully cut off the jug just above the powder level and remove the whole top half of the powder, a good 2-3 pounds, to make sure none of the 2400 was blended in... but for $49, I think I will just toss it to be safe.

Anyone with Quickload want to figure the pressure of 47 gr of 2400 with a 200 gr bullet in an 8mm? That was what was in the case, apparently being a little lighter by volume than the 867.

Finally- I didn't mention this earlier; but I DID hit the target- and there is no leading in the bore!!!! A testament to Felix and his lube that apparently even 100,000ish PSI and an unknown velocity (I'd guess 3-4000 fps) didn't lead the bore.

First: I have to admit I'm eating a little crow here. I had previously assumed that anyone who blew up a gun MUST be doing something wrong- and maybe I was, but for the life of me, I can't figure out what happened! I'm ok, a few pieces of powder burnt my cheek and I chipped one lens in my glasses, but was rattled to say the least.

Gun: Portuguese Mauser-Verguiero, 8mm. I had shot this gun hundreds, perhaps thousands of times before, with all manner of cast, jacketed, and surplus rounds (never turk as it is a bit hot).

So I go out, fire 15 rounds of my 'go to' load of 18 gr of Alliant 2400, with excellent accuracy. This gun headspaced fine, and never had sticky bolt lift.

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. I was assured on many threads here that you CANNOT stuff enough of these into a case to cause issue, and previous experiments had borne that out. I have fired 50, then 55 grains of this powder in other 8mms with this bullet with no issues, lots of unburnt powder, and so I went up a notch. I have mainly been working with the 872, but this season started on the 867 and found it to perform largely the same. So I filled an 8mm case to the base of the neck- about 60 gr- with WC 867. Primed with a mag primer, firing a 200 gr NOE bullet sized to .325", gas checked, lubed with Felix lube, ACWW. Fired one round. Normal report, normal recoil, no issues as regards to anything. Fired case showed normal pressure signs. Still a few unburnt powder kernels in the case when I tapped it, but fewer than before. I was actually feeling rather happy, thinking that enough powder had finally been reached to eliminate most of the unburnt mummies. Bore on this gun slugs to .324".

Second round: BOOM! As the smoke cleared I noticed in order: 1. My glasses were covered in soot, grease, and chipped. 2. Gun was now lying on the ground in front of me. 3. A piece of wood was blown out of the side of the stock below the gas escape hole. 4. I was bleeding from 3 small cuts to the cheek, 2 to the nose, one to the eyebrow, and one to the forehead. 5. I'm ok. Wounds are superficial. 6. Bolt has been re-cocked by the force of the explosion. Ejector spring is bowed out. 7. Bolt won't open.

I took the gun to my smith who works just down the road. He managed to get the bolt open by taking off the barrel and trashing what was left of the extractor. Further observations: 8. Case is totally trashed, primer spit, turned into a flat disc. 9. Atomized brass is everywhere. 10. There is a small crack in the receiver by the gas escape hole. 11. The lower lug was set back into the receiver about 1/32". Less above, but still noticeable. 12. Part of one lug was sheared off. 13. Part of the bolt shroud was fractured and missing.

I have no idea where any of these parts went.

See pictures below. Please tell me what you think happened. I have a theory but want to hold off so not as to spoil your speculation.

Be warned about the WC867 powder...

This is the type of bullet I was firing:
Image deleted as I can only post 10 max.

This is the case fired beforehand with the same load that destroyed the gun. Note no issues:


The first thing I noticed- the wood missing from the stock:


The remnants of the case in the barrel:


The flattened primer:


The crack in the receiver and the lug set back on the right and left sides of the pic, respectively:


Partially sheared bolt head lug. Note it didn't shear at the base of the lug, which was taking the pressure, but rather appears to have been cut by the hot gas blasting over it; though I suppose the sudden impact might have just shattered it unpredictably:


Sheared off shroud:


Bowed out ejector spring:


Let me know what you all think.

[para45lda]

I think you were pretty lucky and that rifle is a lot stronger than I would have thought.

Other than that I don't know but I'm glad you're ok.

Wes

[Milanodan]

Sounds like the graphite deterrent coating somehow burned off before the powder itself ignited. Then you had 60 grains of a faster powder than Bullseye, and the now-heated naked powder thought it was a "real hot" day. Gross overpressure.

[DeanWinchester]

Is it the guns fault or could it be that you had a catastrophic brass failure?

Glocks are tough but when that brass blows out from the unsupported chamber, they look a lot like your poor old Mauser. Sorry about your rifle. Maybe the trigger guard, magazine spring and follower can be saved? Don't look like much else is worth more than going rate for scrap.

[jonk]

Is it the guns fault or could it be that you had a catastrophic brass failure?

Glocks are tough but when that brass blows out from the unsupported chamber, they look a lot like your poor old Mauser. Sorry about your rifle. Maybe the trigger guard, magazine spring and follower can be saved? Don't look like much else is worth more than going rate for scrap.

That was my first thought; however as trashed as the brass is, there is no crack from the rim to the primer visible, and even a loose primer pocket- which there wasn't, I would have caught that on loading- wouldn't cause THIS much problem. I suppose an occlusion in the brass is possible as an answer, but that wouldn't have lead to the primer flattening. My gunsmith felt it was a gross overpressure, not a brass failure. I had fired this brass a number of times before and think it would have blown before this if a brass fault.

[MajorJim]

Can't tell from the pics - is there an obstruction in the barrel?

[jonk]

Can't tell from the pics - is there an obstruction in the barrel?

Nope. The previous round fired hit the target I was aiming at- fresh target so I'm sure. Immediately chambered the second. Fired, then boom.

[Char-Gar]

I agree with your gunsmith that it was gross overpressure. Now how did that come to be is the question?

Assuming that everything you said is correct and you did indeed use the powder you thought you were using and now another can by mistake, I can only come up with one possibility. This is the famous SEE detonation caused by to small a charge of slow burning powder.

So the question is, did you visually check the powder level in each case before seating the bullets? If you did not, then I think there is the problem. Powder measures can malfunction and progressive presses can throw light charges even though the makers tell you they cannot. Never, never load a round without visual examination of the powder charge is my hard and fast rule.

[jonk]

I agree with your gunsmith that it was gross overpressure. Now how did that come to be is the question?

Assuming that everything you said is correct and you did indeed use the powder you thought you were using and now another can by mistake, I can only come up with one possibility. This is the famous SEE detonation caused by to small a charge of slow burning powder.

So the question is, did you visually check the powder level in each case before seating the bullets? If you did not, then I think there is the problem. Powder measures can malfunction and progressive presses can throw light charges even though the makers tell you they cannot. Never, never load a round without visual examination of the powder charge is my hard and fast rule.

1. Absolutely sure on the powder. It's the only powder I have in an 8lb jug of that style; the 872 I have at another location entirely.

2. I was using an RCBS Uniflow. I wish I could say I thoroughly visually inspected each case- and I know I gave them a once over, but looking at a whole tray I don't dispute that I could have missed one. If that's the case I would say it was either operator error charging the case- not rotating the handle all the way and/or doing it too fast, not letting the powder settle into the dispenser- or the powder bridged, but that's not common with spherical powders, and I would have noticed on the next round that 'whoa, wait, this powder is dumping out of the case, what happened' as the remaining 'stuck' charge would have then flowed out. But I'm usually pretty good about looking in each case with a flashlight while in the tray, so if this happened, it means I stared right at it and didn't see it. I'd further think that I DID inspect each case, as depending how the charge dropped, I had to tap a few of the cases to get the powder to settle enough to reach the base of the neck. Since I had to do this on about a third of the cases, I really don't think I overlooked any of them, though I could have.

We'll chalk that up as one possibility, but I'm not convinced that was it. I'm big enough to admit I'm fallible but I really think I would have seen one case not full. Remember- it would have had to been REALLY low- I know that 50 grains works fine if dirty, so does 55, so even if I had missed something it would have had to have been a half charge or something.

You have, however hit indirectly on my theory, which I'll throw into the mix here.

IF I didn't short charge the case, my thought was this: The bullet was not seated against the rifling, though this gun had a fairly tight, minty throat. 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.

?

[tomme boy]

By the looks of the lug setback, about 100K PSI. just about made you worm food.

[jonk]

By the looks of the lug setback, about 100K PSI. just about made you worm food.

Yeah, I'm well aware that I was lucky. Another 10,000 or 20,000 psi and I have no doubt that the lugs would have sheared off, the receiver would have failed, or both. Had that happened, I'm sure that the bolt would have left the gun and/or shrapnel would have flown back at me. Maybe worm food, but at very least massive injury I'm sure would have resulted.

[doctorggg]

Jonk,

I have experienced 1 blown up M1 Garand from an out of battery detonation and a 40 cal Taurus 101. Neither experience was very pleasant. I know how you feel and we are both lucky to still have all our body parts. It really emphasizes the importance of good safety glasses. I am really glad you are ok.

[tomme boy]

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

[SquirrelHollow]

I don't think this was an instance of secondary detonation.

I think it was contaminated powder, or the wrong powder altogether.

I've seen my share of catastrophic failures (including watching a Ruger Hawkeye grenade last year). On this one, all signs point to a powder issue. Nothing else makes sense.

One note, to partially explain why I think it's a powder issue:
I have done a lot of work with cartridge/bullet/powder combinations that were extremely unusual. In those experiments, I never came across an instance where I could show that the powder (especially ball powders) was being "blown forward" by the primer detonation. To the contrary, I found many instances where the powder kernels were exactly where I left them, but fused into a homogeneous blob (due to failed ignition, from using a powder REALLY inappropriate for the application).


My guess is that there was a bit of some type of faster powder stuck in your Uniflow, and it got mixed into the 867.

[Mk42gunner]

I think the damage to the locking lug was done by the torch effect of the suddenly released gas. If it were chipped from pressure, I would think the rear of the lug would have been chipped, not the front.

The first case doesn't look bad, but I doubt you fired them in the order you loaded them. Have you broken down the remaining rounds to check powder charges yet?

My tought is that it could be caused by soft brass. Have you loaded this particular lot before? Over-annealing causing a soft and dangerous casehead?

Glad you are able to make this report, instead of your next of kin.

Robert

[Bwana]

"So I filled an 8mm case to the base of the neck- about 60 gr- with WC 867. Primed with a mag primer, firing a 200 gr NOE bullet sized to .325", gas checked, lubed with Felix lube, ACWW."
Let's see, we are told about the powder, some kind of "mag" primer, the boolit, and lube. What aren't we told? That would be, the primer used, and the case type and the case's history. I see a "F". Was it Federal? Was it a reformed FA 30-06 case? Was it ever subjected to an annealing? How many loadings, what the headspacing on the case? Many questions I'd like to know the answer to before rendering an opinion as to how this happened.

[DrB]

As slow as the powder burns I wonder if you might have had a glob or sluice of unburned powder in the bore of suffcient quantity to obstruct the bore? I have no practical idea as to whether this could happen. It is too bad you can't safely fire some of these slow powder loads vertically and inspect the chamber/fired case for the quantity of residue. Seems like that might give you some idea as to how likely the problem might be....

A contaminated powder measure also seems a possibility. Had you loaded a faster powder immediately before?

Lastly, I believe you said the brass had been fired several times... Have you checked brass length in comparison to your chamber? Could a long piece of brass seated into your throat/bullet? I am sceptical that that would result in a blowup with lead bullets with powder so slow... Rather I would think the bullet would just size down. Also, you probably would notice the resistance when camming the bolt.

Excess unburned powder in the bore or contaminated powder are the principle thoughts I have...

Glad you are ok.

[madsenshooter]

"So I filled an 8mm case to the base of the neck- about 60 gr- with WC 867. Primed with a mag primer, firing a 200 gr NOE bullet sized to .325", gas checked, lubed with Felix lube, ACWW."
Let's see, we are told about the powder, some kind of "mag" primer, the boolit, and lube. What aren't we told? That would be, the primer used, and the case type and the case's history. I see a "F". Was it Federal? Was it a reformed FA 30-06 case? Was it ever subjected to an annealing? How many loadings, what the headspacing on the case? Many questions I'd like to know the answer to before rendering an opinion as to how this happened.

Now there's a good question. There is some FA brass that is soft in the head compared to other GI brass. Thick brass, soft head = blown primer. Happened to me in my Garand last year. All other loads in LC brass were ok. I think it was FA57 brass, but might have been SL, can't recall for sure!

[perotter]

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

[swheeler]

Maybe some of that ball powder wedged between the neck and the bullet at ignition locking the bullet there. Remove the body of the case removed from the chamber and see if the neck went downrange with the bullet.