An interesting case!!


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P95Carry
January 14, 2006, 09:35 PM
One of the guys at a shoot this afternoon was enjoying throwing lead thru his old Mossin - M44 IIRC - anyways he had a can of VERY mixed 7.62x54R - all sorts!!!

This one came out after a seemingly normal feeling shot but hey - look at this case (a steel one) - I have seen head sep's and other things but never this degree of splitting apart!!! :eek:


http://www.acbsystems.com/boards/thr/shoot7/762x54r-fail-379-s.jpg

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BTW - this was the glorious weather we had - after days of mild and pleasant!!! I shot more breeze by the fire than lead!!


http://www.acbsystems.com/boards/thr/shoot7/f-nutz-06-686-s.jpg

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taliv
January 14, 2006, 09:40 PM
wow, that is interesting. especially how it's not one continuous crack vertically, and it appears to wrap around. bizarre!

any separation on the other side of the case?

primer doesn't look unusual

P95Carry
January 14, 2006, 09:45 PM
Bizarre indeed!! I didn't take a pic of other side because it shows minimal problem - just one small gas burn-thru hole just below neck.

The primer is just fine.

Dionysusigma
January 14, 2006, 09:49 PM
And people say that the Mosin Nagant is obsolete... :rolleyes:

Reminds me of a quote...
You're so ugly you could be a modern art masterpiece!
I'd get that casing made into a paperweight. :)

taliv
January 14, 2006, 10:06 PM
hey, p95, i've been staring at this for a few minutes and it looks brittle. probably a long shot, but it just occured to me that the cold might be a factor. i'd be curious if you have another case with the same headstamp in that mixed bag... measure that steel case before and after leaving it out in the snow, to see how much it contracts.

i've never had any experience with steel cases, as i almost exclusively reload brass. is steel known to have cold weather issues?

P95Carry
January 14, 2006, 10:15 PM
taliv - no I really don't think cold was an issue - it had gotten below freezing but not that bad.

I suspect this was excessively thin-walled stuff and perhaps too the steel was in some way embrittled - not enough compliance (as with brass or good steel) to withstand flexing. This was very old stuff I think, tho head stamp does not give too much info - two stampings ''188'' and ''45'' so if 1945 issue well ..........!!

Could be too the chamber was well plus on tolerance although most cases ejected were just fine.

This is the only instance I have seen where failure was so severe. Wolf steel I have never seen fail.

Dionysusigma
January 14, 2006, 10:19 PM
Is steel known to have cold weather issues?
Have you ever stuck a jar under a hot water faucet to remove the lid? Same principle, although working the other way; I think this is cold-related as well.

I personally think it contracted, and in doing so became +/-1mm too small for spec. It then split while expanding in the chamber. My main reason for thinking this is that you only see apparent oxidation on a couple of spots, not the whole crack(s), which says to me that it cracked after the powder ignited. Otherwise, more powder would've gotten out and left its mark near the cracks. I'd blame poor metallurgy and (of course) poor quality control.

mete
January 14, 2006, 10:24 PM
Defective steel since the fracture is a bit strange !!

rero360
January 14, 2006, 11:47 PM
yeah, i would have to agree, very bizarre

sctman800
January 15, 2006, 02:09 AM
My mosins have been getting a regular diet of 1980's Polish 7.62x54 and neck splits are not uncommon. Now that case was a lot worse than any I have seen before but I wouldn't worry about it unless I started seeing it happen a lot. Old Mosins are tough. Jim.

rust collector
January 15, 2006, 12:32 PM
The metal may have been weakened by a mercuric primer. Could also have been improperly heat treated but whatever the cause, I'd be inclined to cull similar headstamps out of the ammo supply!

P95Carry
January 15, 2006, 02:57 PM
The headstamp has but two bits of info - ''188'' and opposite that ''45'' !

It is obviously old and the steel would seem to have lost any ductility - one could almost be forgiven for imagining the splits side was where the powder rested in storage over many years and was somehow causing some corrosion internally.

Anyways - just one for the 'interesting cases' archive!:)

taliv
January 15, 2006, 06:50 PM
ok... again, i only shoot ammo i loaded, so i know zilch about old, corrosive ammo...

so P95, for the sake of argument, let's say it was internally corroded. is that a warning for all the folks stockpiling wolf? or does it not apply because of modern powder coatings? are wolf cases laquered on the inside too? would that help?

i know some old primers were corrosive when they were ignited, but i'd never thought about powder just sitting there in the case being corrosive.

P95Carry
January 15, 2006, 06:57 PM
taliv - this is without doubt ''geriatric'' ammo of first order! :D My thinking on the powder is pure speculation.!!

I'd say that modern steel cased ammo will almost certainly be produced to a high enough standard to permit long term storage in reasonable conditions.

I was purely musing on what might have weakened that case and reduced the steel ductility so much.

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