How to blowup your rifle

[Riflehunter1776]

I generally think of these things (absent the obvious) as perfect storms. The cumulative effect of all the little things.
I vaguely remember someone shooting oversized bullets without catastrophic events. Maybe Ackley, but I don't have the books any more.

yep, that was Ackley.

also, the germans used to fire .323 bullets in the .318 Gew88's. Of course they modified the leade in order to squeeze them down to size, and there was excessive recoil, but I never read anything about those weak actions blowing apart regularly - not like our low number 03's anyway.

 

[Pdvdh]

If a 91.5 powder charge got into a 230 load, u would have been 3.5 over max.

This is the most plausible explanation. Too much powder = too much pressure. Simple as simple gets.

When loading different bullets with different powder charge weights, we must all remain vigilant.

All the other explanations are long odds - at best. Some appear based on nothing more than superstition and overambitious imaginations.

Humidity? Are we serious? We'd all be dead by now if humidity locked up our bolt actions and turned them into scrap metal.

 

[pawater]

I scanned over this relatively quick. I am thinking about the seating depth since you were loading two different bullets to shoot and were adjusting your seating die, Is there a chance your rounds were too long and got closer to the lands?

 

[J E Custom]

I generally think of these things (absent the obvious) as perfect storms. The cumulative effect of all the little things.
I vaguely remember someone shooting oversized bullets without catastrophic events. Maybe Ackley, but I don't have the books any more.

Po Ackley Did that, purely to find out the effects of it. I don't know how far he went, but I know he fired a 8mm bullet in a 30/06 without catastrophic results. But back then, no one loaded to the max because there were many rifles that were not designed for anything more than
52 to 53,000 LUPs and many were around 48,000 LUPs (Lead units of Pressure).

Pre world war 2, Many of The old bolt guns with rear locking lugs, were notorious for blowing out the back of the action If loaded hard.

When Roy Weatherby decided to start manufacturing rifles He started with the Mauser action. Feeling he needed a stronger action for his Big cartridges, He designed the Mark 5 and the rest is history. He even had White Laboratory's do a destructive test on all commercial actions at the time to do a comparison of strength.

I have tried to get a copy of this Test, but it is proprietary and they cant release it. But ALL actions failed except the Mark 5. they over charged the cartridge with faster burning powder and blue all the actions up Destroying them. When the mark 5 was tested this way, It melted the case and brass flowed out all around the bolt locking it up but there were no failures that could cause injuries to a person other maybe a soiled pair of shorts.

The fact that the action did not fail, is testament to the strength of modern actions and gives cause to think about loading beyond the SAMME pressures (which we all have probably done at One time or another) I Have, but no longer now that we have better components and faster cartridges at normal pressures. Why abuse a good action and brass when a cartridge change will probably get you what you want
without excessive pressures that with ANY mistake could be disastrous .

J E CUSTOM

 

[Winkfish]

I had a nice conversation with the folks at Hodgdon this morning and provided them with the load data. The gentleman I spoke with took it to the product and testing folks who care for military contracts and cold weather testing.

Their response was that they suspect the Primer. In their testing they have found challenges with the Federal primer and recommend Winchester for cold weather operation.

 

[Trnelson]

I had a nice conversation with the folks at Hodgdon this morning and provided them with the load data. The gentleman I spoke with took it to the product and testing folks who care for military contracts and cold weather testing.

Their response was that they suspect the Primer. In their testing they have found challenges with the Federal primer and recommend Winchester for cold weather operation.

Interesting information. Thank you for the follow-up data.

 

[HARPERC]

.....This is the most plausible explanation. Too much powder = too much pressure. Simple as simple gets....

I can't argue with that! However, we see max loads vary from manual to manual. As much as we like to scoff at lawyer loads, there are legitimate variables, and likely someone saw something that indicated a good place to stop. It's a complex hobby encompassing chemistry, metallurgy, machining tolerances, and environmental conditions on all of the above.

Yes the 5-10% reduction from "max loads" recommended in many sources likely would have saved this rifle.

Yes operator error has to be considered, and it's easy, and comforting to let it go at that, but I believe every once in awhile (while we're waiting for ice out) to bat it around a little.

 

[J E Custom]

I had a nice conversation with the folks at Hodgdon this morning and provided them with the load data. The gentleman I spoke with took it to the product and testing folks who care for military contracts and cold weather testing.

Their response was that they suspect the Primer. In their testing they have found challenges with the Federal primer and recommend Winchester for cold weather operation.

Buyer Beware !!!. If you talk to Federal, They will probably say it was the Hodgdon powder. Manufactures will never admit that there products were the problem.

It is good that you are doing follow-ups on this with the manufactures, but don't expect a lot. It is always the other guys fault or the owners responsibilities when all else fails.

J E CUSTOM

 

[bigngreen]

I doubt you can get enough retumbo in the case to swage the case head, as the numbers were ran earlier in this thread a 91.5 gr load would likely produce some pressure signs but to swage the lettering flat take significantly more especially with Retumbo. Detonation would create this kind of thing.
For it to be a load the rounds would need to be loaded and shot in the same sequence since all other rounds were right, I could see loading the first round with the 190 load by mistake but even at that I doubt you'd create this kind of pressure.

 

[Scooterbum]

Bng,

Good thoughts.

I considered the excursion to be somewhat less than dramatic. No separation, and the pressure venting was unidirectional, thru the primer tunnel. With enuf psig to swage outward once established in the tunnel, creating an expansion chamber at that point in time. Prior to outward, most psig was swaging the lettering.

Just my thoughts.

 

[Bowfishn]

If we take the velocity readings as accurate then the ba of the powder lot is .3795 to get 3100 fps with the 190 ABLR @ 71K pressure.
Using that ba and running numbers on the 230 Bergers we would have a pressure of 74K, at 70 deg far. testing in cold temps would not necessarily show any signs of pressure as 0 deg far. shows 65K pressure. The higher ba would however allow for greater pressure with a problem that may have occurred.
86.8 gr Retumbo with ba of .3795, 3.600" COAL, 230 Berger, -10 deg far, would give a velocity of 2806 fps out of a 26" barrel @ 63,865 psi.
If we jammed the bullet all the way into the cartridge speed and pressure would be 3030 fps @ 91,506 psi. ( doubt you could jam it deep enough to get to that point and velocity is low )
If we loaded 91.5 grains 102.3% fill 2932 fps @ 76,366 psi. ( maybe but lacks velocity)
If we loaded 100 grains 111% fill 3154 fps @ 105,321 psi. ( I doubt you could pack that much in)
Jamming the lands may get it to 75K but velocity is 2882 fps which is low.
Combination of above, maybe but I doubt it.
I know these figures are derived from QL calculations, but I believe to a degree they are accurate. JMO and right now that is all we have is speculation.
My theory is, the rifle and bullet was allowed to drop to ambient temp of -10 degrees far. something it had not been allowed to do the day before. The cold weather did cause a hang fire jamming bullet and compacting powder partway into barrel, pressures rose causing remaining powder to detonate causing massive spike in pressure sticking bolt shut and sending bullet out at 3129 fps.
Years ago H110 powder in magnum handguns caused a similar problem when load was reduced and it caused hang fire resulting in detonation and pressure spikes.

 

[Scooterbum]

I have thought about detonation, but wouldn't there be noise, recoil, and if enough, parts departing?

 

[Barrelnut]

The cold weather did cause a hang fire jamming bullet and compacting powder partway into barrel, pressures rose causing remaining powder to detonate causing massive spike in pressure sticking bolt shut and sending bullet out at 3129 fps.

Yes. The primer, whether due to the cold of a just a circumstance weak primer, caused the very cold Retumbo to have erratic ignition and it pretty much caused a slight hang fire. I agree that it's the only way to get the pressures needed.

There seem to be to many other shooters posting saying they had spikes with retumbo in very cold weather. retumbo may be a little hard to ignite when it is extremely cold. It is probably somewhat marganial too. That is why most don't see it and some do.

 

[adam32]

I doubt you can get enough retumbo in the case to swage the case head, as the numbers were ran earlier in this thread a 91.5 gr load would likely produce some pressure signs but to swage the lettering flat take significantly more especially with Retumbo. Detonation would create this kind of thing.
For it to be a load the rounds would need to be loaded and shot in the same sequence since all other rounds were right, I could see loading the first round with the 190 load by mistake but even at that I doubt you'd create this kind of pressure.

That's been my thought too, I don't think enough Retumbo would fit in the case to cause these issues.

We've tested 700 actions to 175,000psi and the barrel spun off fine. Turned a .243 Win into a belted mag by doing so.

Screwed it back on and went to 210,000psi and then the action did end up in 2 pieces.

A 3 grain over load will not cause what the OP experienced in my opinion.

Like as been said, perhaps just a "perfect storm" of several things.