Weird case stretch? Whats the cause of this?

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LoonWulf

LoonWulf

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I found these while scrounging brass, and doing a light clean up at the range I use. Ive never seen this and my only thoughts was a semi opening up early. I also havent seen MFS ammo for sale too many places here, and was thinking about talking to the guys i know at the stores just to give them a heads up, maybe they know who purchased some these (unlikely, there ARE alot of 06s running around).

Ive used MFS ammo quite a bit in my Mini-14 and had no issues. Also after finding these cases (and a few more that looked to be from the same gun but with less obvious stretch) i decided to look around for more MFS stamped cases (or cases with the other markings), and i found some .308 but none showed any abnormalities. Leads me to believe a gun issue.
I figgured id ask and see what people thought?



 
Classic symptom of a headspace problem. What are you shooting it in?

M
 
Its not mine, i found it while cleaning up. I would be interested to see what was firing them....not up close mind you but id like to know.

I was also out last saturday, and didnt notice any of the shiney ones, and they were right where i had my table that day. The corroded one looks to be from the same gun, but its obviously not fresh.
 
Well, someone has a problem. Looks like 30-06

I hope they found out and took it to get fixed.

M
 
I hope so, from the new and corroded cases tho i get the fealing they havent.
 
I found a couple of those cases too, get your trusty magnet out, they are steel with a brass plating.
 
I think they are steel & that is the stretch belt, fired from a military rifle............
 
Guys, can you expand on that please? I am looking at a REBATED ring near the bottom. Is THAT what you are saying was pushed in as the result of a headspace issue or that the rest of the cartridge expanded around it!? Or what!?!?

I'm missing something obviously...
 
Rimless cartridges are headspaced to the shoulder of the cartridge. Headspacing issues can cause excessive stretching as the cartridge expands until the shoulder of the cartridge contacts the corresponding location in the chamber. Firing such a firearm with such an extreme headspace problem can be dangerous as it will likely lead to a case rupture at some point.
 
Those are steel cases MFS ammo is russian made as far as my limited research shows. Im honestly surprized those cases held together. I dont think ive ever seen a case of bad head space that extreme.
 
Guys, can you expand on that please? I am looking at a REBATED ring near the bottom. Is THAT what you are saying was pushed in as the result of a headspace issue or that the rest of the cartridge expanded around it!? Or what!?!?
Click to expand...
Headspace is the distance between the base (head) of the cartridge and the breechblock.

Bottlerneck rimless cases headspace on the shoulder -- so headspace is measured from a point on the shoulder, not on the base (head.)

In the case of these cartridges, there is excess headspace -- the cartridge goes too deeply into the chamber before the shoulder of the cartridge makes contact with the shoulder of the chamber -- think of this as leaving a gap between the bolt face and the base of the cartridge.

When the cartridge is fired, high pressure gas (on the order of 50,000 PSI) expands the case, forcing it to tightly grip the walls of the chamber, sealing the chamber and preventing the gas from blowing back into the shooter's face.

But the heads of these cases were unsupported, so they were free to expand backwards until they hit the bolt face -- that's what caused those stretch marks. And the head can separate, allowing high pressure gas to blow back into the rifle's action, often wrecking it and endangering the shooter.
 
What is with everyone screaming HEADSPACE! Over every strange casing nowadays?

You guys do realize that steel cased Russian 30-06 comes with that rebated section above the case head right?

DSCN6627-500x500.JPG


posted via mobile device.
 
I have some Grizzly ammo that has that. I confess I looked for a long time at the pics in the OP scratching my head, because I've see that groove before.

I always assumed that it was there to keep an unwary person from putting it in a reloading press, since it shoes up on the brass plated steel, berdan primed ammo.
 
If there was really that much of a headspace issue; how would the firing pin hit the primer??

You guys do realize that steel cased Russian 30-06 comes with that rebated section above the case head right?
Click to expand...

I didn't because I have never bought that ammo before, but it certainly answers the question posted in the OP.
 
Dale;
Thanks for answering my specific question. I know what headspace is, etc., but I'd never seen a case like that with the rebate I mentioned and thought THAT was what people were talking about and couldn't for the life of me figure how a chamber would do that per a spacing problem.

So, was everyone else answering a question about that rebate totally incorrectly!?
 
Another question if you good folks dont mind. Why did some of the cases show very little of that rebate? Do the expand out to fill it some times?
 
The 2 brass on the left look like case head seperations. Hard to tell from the photo. 2012031417393945.gif Factory new Ammo, "Golden Bear steel Brass plated case, 145Gr, FMJ bullet" > Rebated30-06.jpg
 
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I do apologize those were crappy pictures. The cases are still sitting in my truck if some one wants better ones, I had come to the impression it was decided that there was nothing wrong with them.
 
Still seems like a bad idea. Some LC 308 Match brass had a band of light striations around the base of the brass in about the same locale. But, that seems like the worst place to put a deep (identifying?) groove. I wonder why they did it.

M
 
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