Not a great way to begin a thread on load development but....

[Thud]

Good thing your both ok.
Is there a possibility of a carbon ring in the throat. How many rounds did you shoot before the situation happened.

 

[RyeGuy]

I know someone already mentioned “wrong bullet in the box” But is that really possible? Would being 20 thou off lands be far enough out to chamber a 30 cal bullet? His reload methods sounds pretty thorough so I’d say that’s ruled out. Leaving obstruction or case failure, Or action failure! You should get decent pressure signs before splitting an action.
I’d get CA involved tomorrow.
Glad you’re ok. Damn that’s scary stuff.

 

[searcher]

I'm not sold on excessive bolt thrust. Because you were running through your string in 3/10th grain increments, you would surely have seen signs of excessive bolt thrust at 3/10th grains less - and possibly much lower than that. You don't go from "everything's fine" to blowing the barrel off the gun in 3/10th grains without signs leading up to that. But - if one of the bullets in your box of bullets was of larger diameter, all you might have noticed was a little harder seating on that one round. It seems to me the bullet got to the end of the throat, jammed, and blew the barrel off right at that juncture, thus no bulges further down the bore and no indicators leading up to that point. I think something like that is the most plausible explanation, though there are the "outliers", like defective barrel, massive error in charging, heavier bullet in the mix, etc. There would have been sudden and dangerous pressure buildup, for sure - everything you encountered. It is amazing you did not get seriously injured or worse. I always try to keep; these types of situations in mind as reason to always wear my shooting glasses when hunting - when it can easily be forgotten. I like to think I have already made all my mistakes - but likely not - and sometimes things aren't our fault.

 

[lawman29]

Rare:
Cartridge manufacturing defect in solid case head

 

[64Rambler]

Take those other 2 rounds apart and reweigh the powder charge.

 

[1shot]

I'm going with either an errant large projectile or a bridged powder charge with the under charged round not fired yet. Bottom line, I'm thankful no one was injured.

 

[243winxb]

The bolt was still in the lock position

The receiver failed. The recoil lug got bent as the barrel moved forward, away from the receiver.
Or some fast burning pistol powder found its way into the case.

 

[Webster]

I've been reloading for about 10 years in various calibers. Mainly 30-06, but also 6.5 Grendel, 20 Practical 243, 308 etc... and never had a problem till this happened. Looking for some insight on what possibly happened as I can't figure it out and all of the people I've talked to that I know and at the range I go to haven't been able to crack the mystery either.

As a baseline, I feel I'm conservative about reloading. There is always more to learn, but one thing I always do (since I'm loading low volumes) is double weigh my charge loads just to make sure they are what I think they are.

I bought a 280AI as I wanted a lighter weight mountain gun for elk hunting 22" 1-9 Twist. Did some load development using ladder load/3 shot strings with a variety of bullets (Nosler AB, Berger, Sierra GK, Hornady ELDx, Barnes TTSx) but focusing on H4831SC since I had it, it was listed with much of the published reloading information and others in various forms have had good results. Measured the CTBO to Ogive for each bullet I was using and then backed that off by 0.02 using the Hornady tool. I started the ladders at 55.0 grains (bottom of the Nosler data) with 160 grain bullets (preferred Elk weight for me), moved up in 0.3 grain increments and maxed out at 57.0 grains for these ladders. Recipe = Virgin 280AI Peterson brass, CCI LRP's, H4831SC. At the range, used a Magneto speed for velocity and was getting around mid 2600's for velocity which is well within the 3-4 sources for reloading data that I used when determining loading parameters. My philosophy is to try and find the softest load that produces the best accuracy and still allow the bullet to perform as intended. All good at this point. Fired 90 rounds that day.

My youngest also bought a 280AI from a different manufacturer and wanted to do some load development as he hunts our ranch as well. We used the same reloading source books (just to double check) and loaded around 50 rounds (ladders for load development) and I loaded another 18 with same CCI LRP's, Virgin Peterson brass, the Nosler 160 AB's and the H4831SC starting at 56.5 (accuracy node based on initial round of shooting) and moving up in 0.3 grain increments His velocities out of his gun were similar to the first strings I shot (Mid 2600's) as measured by the Magneto Speed. Again - all good at this point after 140 rounds fired in two different guns.

I started shooting my rounds (56.5 grains) and was getting velocities of mid 2700's. We scope each shot to check placement before firing again. Got to the 57.1 grain string (11 shots fired) and was just starting to touch 2800 fps with the last shot at the 57.1 grains. I check for pressure signs on the cases after firing just to make sure I'm not missing anything and saw nothing out of the ordinary. First shot at 57.4 grains (next step up) blew the action out of the gun, scared the living )(#&*&$ out of me and my boy and resulted in some four letter words being uttered. Luckily no one was hurt.

My first thought was a squib load, but we registered 2800fps on the shot before and saw the hole on the target down range. The barrel was intact and showed no bulges (that I could see) although it was no longer attached to the gun. You can see the base of the barrel with the cartridge still in the barrel. The shot where the action fragged still recorded 2600 fps which I can't wrap my head around. I've attached pictures.

I recognize there are most likely to be (hopefully) further questions and happy to answer but really just looking to see what I could have done differently, particuarly going forward. I'm a little gun shy (pun intended) at this point and while I have never had an issue before, I don't ever want another issue again.

Thanks

A cleaning patch in the bore?

 

[timeout]

It's been mentioned in an earlier post but what is your OD measurement at the .200" mark? As I do a ladder test I measure each piece of brass to check on expansion numbers. I may be all wet, but I think that is a very important step in keeping an "eye" on over pressure signs.

 

[farmerjohn]

Hey Feller, after 60 plus years of reloading and reading from Hatcher and Ackley, I'm going waaaay out on a limb and call that a faulty receiver. I would have an independent lab do an analysis on that receiver and find out what the exact specs are as opposed to what they are supposed to be BEFORE I contacted the manufacturer and go from there. My 2 cents worth....and thank the Lord you are both ok.. John

 

[timeout]

Receiver failure had entered my mind but, looking at the head of that brass and bolt face says way over pressure on that particular round, not simply a receiver failure. The $64k question is why? I'm leaning toward something wrong with the brass in the neck area causing the bullet to be pinched. I use Wilson seating dies and an arbor press so it is apparent if I have a seating issue. It's not as easy to detect a change in seating pressure when using a loading press for seating. I think you probably would have noticed an irregularity when closing the bolt if you didn't have any neck clearance. Maybe, maybe not? I sure hope that you get to the bottom of this. I would be scared sh!tless to ever reload again if this happened to me. Thank God no one was injured or killed!

 

[DaveTooley]

I haven't read every reply but I have an example of this kind of failure in the shop. This was caused by extremely high pressure. Notice in this case the part of the cartridge case that's missing as well as the copper wash extending down the action. The failure points are exactly as happened here. I know what happened in my case although I don't think it's relative here. In my case it was using incorrect powder causing catastrophic case failure from extremely high pressure. Here pressure was high enough that escaping gas cut steel as passed down the bolt in the extractor slot. We estimated the pressure to be around 110,000 to 120,000 PSI. The pressure shock wave from a violently expanding barrel tenon gets transferred to the receiver along with the pressure of the escaping gas and you can see the failure points. The odd thing in my case was the barrel was not deformed at all. The expansion of the tenon did not exceed the yield point of the steel. I head spaced it on another action and it performed perfectly.

 

[243winxb]

looking at the head of that brass

It was the only part of the brass, that was not supported. The brass remained in the barrel chamber.

Unsupported brass fails.

 

[timeout]

It was the only part of the brass, that was not supported. The brass remained in the barrel chamber.

Unsupported brass fails.
View attachment 1738256

Every rifle that I own has unsupported brass hanging over the edge. Why did this one fail is the question? Obviously over pressure. What caused the over pressure?

 

[243winxb]

Since this was virgin brass would there have been the possibility of excessive case lube from the factory? I say that because I pulled it straight out of the sealed boxes from Peterson and loaded them.

If case volume was reduce by foreign matter being inside the new brass, i think the powder would have over flowed the brass.

You posted, 1 piece of brass did not fit the shell holder. This puts the brass in guestion, as possibly defective?

I did have another piece of brass from them that I couldn't get in my shell holder on my primer seater. It was the only one like that. I set it aside

The Extractor Type: M16-style extractor for improved reliability.
No "Three Rings of Steel" like a Remington 700 action.

 

[K22]

add - the SEE scenario others have mentioned is another possibility for excessive bolt thrust. I don't place a great deal of confidence in that theory because it's a subject widely disputed and apparently not repeatable under test conditions.

I remember reading many years ago that White Laboratories ran a series of tests trying to create the SSE scenario and were unable to produce it. The initial reason was to investigate claims of low charges of Bullsyse Powder in target loads for pistol since a few pistols had been "blown up". They concluded that the probably reason for the failures were due to obstructions in the barrel. I don't know if they ever tested for low charges of rifle.

 

[SmokinJoe]

Well, I have read this entire thread because when something like this happens it is of concern to all of us. As others said, glad y'all weren't injured or worse. After reading everything the one thing that concerns me is that you loaded up new brass right out of the box without checking the OAL on it beforehand. Usually the chamber OAL exceeds cartridge specs a little so USUALLY a slightly long piece of brass doesn't make much difference. I know that you are using good quality components but things do happen. My procedure on all new rifles/barrels is to check chamber OAL with one of those little plugs from Brownell's in a neck shortened case and to measure the actual neck diameter with small hole gages or pin gages so you know the reality of your rifle. Then you need to check brass OAL and loaded neck diameter to know for sure that everything is as you want it to be. My take on this accident is that the chamber OAL is on the short side and the failed brass was just a little too long. At this point you can't check the chamber but you can check your brass to see if there is any length discrepancy worth worrying about and compare it to SAAMI. Hope this helps, really scary deal.

 

[dellet]

You noted that the bolt was still in the locked down position. But the photo, that is not the case, or it might be the problem.

Is there any chance this rifle could be fired without the bolt fully closed?
Note in the photo, the lugs are not where they should be.



The other odd thing is that it does not look like any gas escaped the relief hole.



The case head is about what you get in a gas operated system when it’s over gassed. The extractor is what pulled the missing piece out. Did this happen when the barrel moved forward, or was the chamber not fully closed?



Plenty of brass blown into the ejector andwelded to the chamber, so certainly a lot of pressure

 

[divingin]

I know someone already mentioned “wrong bullet in the box” But is that really possible?

I had a 500 pc box of 168 SMKs that had a single 220gn bullet. It was way longer than the 168s; luckily it was pretty obvious and easy to catch.

 

[Cloudrepair]

Im glad you're ok also.
Im not sure if anyone sees this, but it looks like the action had an existing crack about halfway in from the opening in that action just over the bolt lugs.