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Thread: Split Cases - The Cause Of?

  1. #1

    Split Cases - The Cause Of?

    I recently acquired a 30-06 and a good friend very kindly gave me some 'SAKO Once Fired Cases' to help me on my way.
    I put them all in the tumbler to get a good shine to make inspection easier.
    Well, of the 122 I was given, ten had cracks from the mouth to the shoulder, seven more had cracks in the neck between the shoulder and the mouth and one had multi cracks almost the whole length of the case body.
    Sako is, normally, good brass and I cannot see these faults having been there before the cartridge was fired, so here is my question.
    Do the faults I found indicate a problem with the chamber of the rifle used to fire them in the first instance.
    Has anybody else had this experience with SAKO brass, particularly in 30-06?
    I have had Winchester cartridges with small/short hairline cracks in the case on new ammunition, just a small split from the mouth in most cases and hasn't affected the shot. It just meant the case was not fit for reloading.

  2. #2
    In the industry, the splits from the mouth down to the shoulder are referred fo as "M" style splits. These are ominous, to say the least. It can be the chamber but it is more often the brass and improper annealing. I'd toss the lot.~Muir

  3. #3
    I've tossed the split ones.

  4. #4
    If that brass is of the same lot I would be really careful with it.~Muir

  5. #5
    Quote Originally Posted by Muir
    If that brass is of the same lot I would be really careful with it.~Muir
    I will, thanks.
    I'm quite happy with what to do with them but thought I'd mention them on here to see if anybody else had come across it and not felt happy bringing the subject up.

  6. #6

    Years ago I took part in a bit of a row between the then importer of Norma 6.5 X 55mm. and the user who experienced split cases.
    In this instance the brass was separating horizontally across beneath the shoulder.
    The brass was sent up to me for a look-see and further cross-sectioning as the importer was ready to blame anything and everything but the manufacturing.

    Too much zinc in the alloy will create a tendency to rapid hardening. It happens from time-to-time.
    Too much head-spacing in the chamber can also cause horizontal case separation, and this might only be discovered by the rifle owner if the cases are already quite hard and READY to separate if they encounter the stress of having to lengthen too much during firing.
    (if in doubt about the rifle chamber - have it checked by a reliable gunsmith who BUILDS rifles).
    The first chamber cut by a new chamber reamer is the largest in width and headspacing.
    This should be within the tolerances allowed in the trade and should be proven during proofing.
    As the reamer gets blunted by use - it gets sharpened and narrower - again within allowable tolerances.
    A brand new factory reamer will give a roomy chamber - combine that with hard brass which is NOT elastic enough - - - - - - .

    Time and rattling about can cause 'work hardening' just like a copper fuel pipe in an engine rupturing after years of work vibration.
    Brass is a harder alloy and gets even harder as it gets vibrated or beaten.

    I've opened sealed cardboard boxes of 'vintage' Remington H&H .300 mag and found the case necks split.

    But here's the strange thing - Friends and I have reloaded some brands of .270 cases and .243 so many times that we forgot how many - with no signs of hardening. The time to chuck out was determined by the brass flow and amount of neck trimming done.
    The cases were just getting thinner.
    .22 Hornet cases which are very thin to begin with can give good examples of case wear and cracking.

    On the ssubject of your once-used brass - I'd chuck the lot. If it was a case of desperation then anealing is a possibility, but in this case - 'scuse the pun - brass is not so hard to obtain.

    Some brands od case contain more brass than others - they are heavier and hold a little less powder.
    On the other hand, lighter - roomier and well-known brands such as Norma are on the whole VERY reliable.
    The difference in accuracy in the field between using one brand of case or the other, or even case weights, is so minimal that the average person, and the living target would not notice - even on check zeroing.
    For what it's worth, and everyone has their own valid opinion, just try to batch your cases in weight after checking them through - if it makes you feel happier.

  7. #7
    The reason I asked in the first place was that I was concerned for the original owner and having never seen Brass this bad thought it might have been of interest to others.
    As I said previously, I ditched the split Brass and used a few of the ones salvaged from the batch given me.
    I have used some of them now a few times and they show no signs of deteriation.
    Now I have obtained some PPU ammo, I cannot see me reloading for quite a while as the price of PPU and the quality is good enough for me.

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