Geco factory ammo an almost blow up.

[Bavarianbrit]

A hunting colleague was at the shooting range with factory made Geco ammunition. The gun fired very aggressively. The shot did hit the target, but a lot of gas escaped out of the bolt area and the rifle jammed. He finally got the Mannlicher Schoenauer open I suspect with the rubber hammer and the case came out from the chamber easily with the help of a cleaning rod from the muzzle.
The fired case head looks very wrong to me, as the primer hole appears to be very large. The spent primer didn't come out with the case; it seems to have dissolved and the extractor is now broken. I suspect this is a quality issue with Geco? Too much energy escaping to the rear through the oversized primer hole. See photo.

 

[KimE]

Which cartridge? Its looks very strange.

 

[HonestJohn]

6.5x57r presumably. Yes, blown wide open and even expanded the bottom of the case by the looks of things.

Obviously a primer blowout. You can only guess until inspected and checked for headspace, pin protrusion, dirt or carbon in chamber, obstructions, or component quality. I’m going to guess carbon in chamber due to age and likelihood of never having been cleaned properly

 

[Smellydog]

The high pressure enlarged the flash hole. Even if it was large it shouldn't cause a fail.

 

[Smellydog]

The list is endless.
Wrong powder.
Wrong charge.
Wrong primer.
Blocked barrel.

Take your pick

 

[Bavarianbrit]

Not sure, I will have to ask him.
He is sending the case to the proof house over here and the rifle to a gunsmith for checking of headspace etc.

 

[Liveonce]

Not good, glad nobody was injured. Let us know what the proof house has to say.

proof house may ask for any unfired rounds from the same batch/box.

 

[Bavarianbrit]

He is an over 40 years experienced hunter and has the German RFD status so he knows what he has to do, I assume he made no mistake with the wrong round in the chamber type of.

 

[KimE]

A rechambered 6,5*53r?

 

[HonestJohn]

A rechambered 6,5*53r?

It would be hard to imagine

 

[Apthorpe]

6.5x57r presumably. Yes, blown wide open and even expanded the bottom of the case by the looks of things.

My first guess was Dutch Mannlicher 6.5x53R, although the hole where the primer was seems inexplicably large to me, even allowing for total primer failure. I wonder if there was some major fault in the case head and an annular chunk came out.

Obviously a primer blowout. You can only guess until inspected and checked for headspace, pin protrusion, dirt or carbon in chamber, obstructions, or component quality. I’m going to guess carbon in chamber due to age and likelihood of never having been cleaned properly

Although we can see what appears to be the action and bolt in the background. Both appear to be clear and the barrel removed from the action, which suggests to me he's more likely to be a conscientious gun cleaner and to have a degree of technical knowledge.

 

[Bavarianbrit]

It is a .243 Win the ammo was new bought Geco, I spoke to him last night.

 

[BryanDC]

I made the mistake of buying 3 boxes of Geco softpoints in 7x64.

At 200m the group was more like the spread from a shotgun. I tried to take them back but the shop had ordered in for me in that calibre so wouldn't. I tried speaking to RUAG but they also couldn't care less.

I ended up firing the lot at 100m targets just to use them up. This was about the time that the lead ban was announced so I went over to non-lead a few years ago. Certainly won't be buying Geco again.

 

[Bavarianbrit]

.243 Win has the same shape extractor groove as the .308 the fired case looks more like a rimmed cartridge after the firing/explosion in his chamber, a rimmed cartridge cannot have been wrongly put into the chamber and allowed the bolt to close so I think it must be Gecos .243 ammo fault, he is sending everything off to Deva (the German central proof loading Institute) for appraisal.

 

[HonestJohn]

Jesus!!!! .243!

That’s shocking

 

[Muir]

How did the barrel come to be removed from the action? -Muir

 

[75]

Jeepers, 243???! Assumed it was a rimmed cartridge from the initial photos.

 

[Apthorpe]

Jesus!!!! .243!

That’s shocking

It really is. I came back to this thread because it occurred to me that I don't think you can use rimmed cartridges in a proper Mannlicher-Schoenauer.

The force required to do that to a .243 case must be colossal. One of the things often said about Mannlicher-Schoenauer actions is that they're not particularly strong. That one must have been. The pressure must have been immense.

 

[Dalua]

The 'primer blow-out' is, I guess, a sign of what's happened rather than a cause. I guess the material of the case-head has been squeezed out to make the new 'rim' and left a markedly-enlarged primer-pocket.
So what's happened?
How was the material able to move to form that 'rim'?
Was it fired with the bolt not-quite in battery - allowing space for that to happen even with normal pressure?
Or was it a very high-pressure discharge, which has altered the shape of the case by squeezing brass into spaces accessible to it even when the bolt's properly closed?
Or a high-pressure discharge which 'stretched' the action, allowing the brass to flow as observed?
Ore something else?

In any case, it's good neither case nor bolt failed completely. It will be interesting to know whether the headspace is (still) OK.

 

[75]

The 'primer blow-out' is, I guess, a sign of what's happened rather than a cause. I guess the material of the case-head has been squeezed out to make the new 'rim' and left a markedly-enlarged primer-pocket.
So what's happened.
How was the material able to move to form that 'rim'?
Was it fired with the bolt not-quite in battery - allowing space for that to happen even with normal pressure?
Or was it a very high-pressure discharge, which has altered the shape of the case by squeezing brass into spaces accessible to it even when the bolt's properly closed?

In any case, it's good neither case nor bolt failed completely. It will be interesting to know whether the headspace if (still) OK.

Yep, I'm struggling to get my head around how that "rim" has been formed. Looks broadly consistent around the head, other than the ejector. I'm not familiar with that rifle though so I just looked up a few images of the bolt and the bolt face it broadly flat, with no rebate like I'm used to on Sako / Tikka etc.



So I guess if there's a gap between bolt face and chamber with significant overpressure, the brass will be forced into a rim?