ColinBr
Well-Known Member
Yup was about to post the same
Split Case?
- Thread starter Spikelet
- Start date
C h r i s
Well-Known Member
So we assume the worse of every posting on SD now? I pity the OP. There's nothing in the images that looks fraudulent to me, and no, thankfully I'm not blind. I've seen plenty of split cases like this, and plenty of gas cut chambers as a result, especially if the split occurs around the shoulder.
Spikelet
Well-Known Member
I'm afraid you have misjudged me and I accept your apology.The mystery deepens and well done for assisting with the sectioning and photo. Assuming that it was you who was there and know about that.
If you were there, then clearly that piece of brass was seriously bad. and so might the rest be. Though still not quite clear at what I am looking at.
My mind is not closed, but I have never seen anything quite like this before, and hopefully never will.
As I did say "If I have misjudged you, well, I apologise in advance."
Having tried the paper clip test I couldn't feel any obvious failure line so I cut the case in half using a Dremmel with a fine cutting disc.
I'd assume it would be obvious that the second image I posted was the internal view of the now sliced cartridge. I thought this would be useful for future reference.
If you'd like me to post any additional images to confirm this then let me know.
C h r i s
Well-Known Member
Did you have an independent witness?
Spikelet
Well-Known Member
I'd have definitely had one present if I'd known I was going to get accused of being full of BS.
ChesterP
Well-Known Member
What seems odd is if this was below recommended minimum load, you'd likely have had soot evident on the case head and main body, which it's assumed you've cleaned up with wire wool (low charges often won't obturate well hence burnt powder can make its way down neck and body of case). The split will be pressure related in that a weakness was caused or present in the brass and pressure is what's split the case along the line of weakness. There's an obvious ring on the first photo lower down the case towards the head which as others have observed, can be indicative of insipient case-head separation, normally associated with excessive headspace (brass over sized) yet nothing is seen in the cross sectioned case which is a little unexpected, plus what looks like a parallel internal split forming. This would be expected on the outside face rather than internally, where no evidence of that line is present, due to the stresses acting from the case outwards, unless this damage and the main split were both due to an internal manufacturing defect. On the basis of the evidence on those photos, one can only conclude it is and internal malformation/damage of the case leading to the main external split but it doesn't explain the evident ring in the external photo (usually the start of a waste formation) which should be evident in section. Personally, I would ditch that batch of ammunition and use some fresh new brass. What you've shown only raises more questions than answers which means uncertainty.
These, to me, are the weirdest things on display:
I could maybe, understand how the longitudinal cracks might have started off with a problem in the deep drawing of the case before it was headed, but not so that circumferential crack, red arrows, propagating from where the longitudinal cracks stopped moving.
Nothing like anything I have seen in ductile cartridge brass, but there again I haven't microsectioned many to take a look. Seems to be extremely brittle, which is scarcely believable for any usual cartridge brass, just once or twice fired. Altogether outside my experience, or knowledge.
Good work with the Dremel, you could hardly have done better with a milling machine.
PS:, I see you took that photo with your Xiaomi M2101K6G on 03/10/2022 18:02:57 at GPS coordinates (redacted) plus lots more. info. Maybe best to at least turn off location data for such sorts of photos. Or scrub the exif data before posting. I think The SD does that anyway, but you have linked to postimage, which clearly does not.
I could maybe, understand how the longitudinal cracks might have started off with a problem in the deep drawing of the case before it was headed, but not so that circumferential crack, red arrows, propagating from where the longitudinal cracks stopped moving.
Nothing like anything I have seen in ductile cartridge brass, but there again I haven't microsectioned many to take a look. Seems to be extremely brittle, which is scarcely believable for any usual cartridge brass, just once or twice fired. Altogether outside my experience, or knowledge.
Good work with the Dremel, you could hardly have done better with a milling machine.
PS:, I see you took that photo with your Xiaomi M2101K6G on 03/10/2022 18:02:57 at GPS coordinates (redacted) plus lots more. info. Maybe best to at least turn off location data for such sorts of photos. Or scrub the exif data before posting. I think The SD does that anyway, but you have linked to postimage, which clearly does not.
Smellydog
Well-Known Member
Woo woo, does that mean I win a prize for the least typing and no drama or panic.In addition I have examined the chamber with a camera and can't see any obvious damage as a result of the cartridge failure
No dremiling or saying ' overpressure '?
Oh crap, I said it......
Foxyboy43
Well-Known Member
’Scuse me - there will be NO mention of “winning prizes” unless in the same sentence as “ monthly draw” and “Foxyboy” - is that clear?
Your name is added to mein list! Be afraid, be very afraid!
That's good for morale.In addition I have examined the chamber with a camera and can't see any obvious damage as a result of the cartridge failure
Just an aside here, had a chamber (Any) chamber been gas cut, the next round fired may have needed gunsmith extraction, as has a buddy of mine for that very same reason.
Spikelet
Well-Known Member
That's good for morale.
I was pleased to see a clean looking chamber, that said I hadn't noticed any extraction issues.
I have a very hard time believing that, several different rifle manufacturers (notably HK) have used flutes in chambers to AID extraction.
Much deeper and deliberate cuts than gas cutting from a single split case would achieve.
More likely is the rifle in question has poor primary extraction, often resulting bolt handles being worked loose via a hammer due to stiff loads...
And very UNIFORM TOO, not gas cut.
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