When is a flashhole "off-centre"?

Discussion in 'Reloading' started by LRHWAL, May 25, 2011.

  1. LRHWAL

    LRHWAL Well-Known Member

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    Ok, so I'm a bit anal about most of my reloading.

    On the weekend I opened a new pack of WW 300WM brass to do some sorting.

    The weight variation was great; all less than 1% before doing anything to them, but of the 50 cases more than half had visibly off centre flashholes. I suspect that as I got progressivley more frustrated I was maybe a bit too discerning, but nonetheless...

    As I'm in South Africa I can hardly send them back! I then opened a more recently purchased pack and found only 4 of 50 that I considered too "off-centre".

    I have two questions, as despite years of loading I've never really investigated this beyond culling stuff that looked off!

    1. When is off centre too far off centre?
    2. Has anyone actually tested this and seen if they really result in poorer ammo?

    Thanks.

    WL
     
  2. boomtube

    boomtube Well-Known Member

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    When is a flash hole off center? On Tuesdays!

    Seriously, it's not all that precise. Forget it unless it jars your eyes to see.
     

  3. dig

    dig Well-Known Member

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    Greetings in South Africa! I have run into the same issue with Remington Brass but have not found much of an issue with WW. I normally cull them through visual inspection, you can stick a flash hole tool through from the top of the case, I use one thats not sharp from Lyman, that gives you a better visual of the alignment. Also try rolling them on a flat surface or spinning from the pilot on a trimmer, this makes it easier to see. Not sure it makes a huge difference as I have never tested one again another but certainly part of my QC check and wont hurt.
     
  4. Kevin Thomas

    Kevin Thomas Well-Known Member

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    LRHWAL,

    Don't sweat it, it won't make any difference. Some years ago, Creighton Audette did a series of pretty exhaustive tests on this issue for the NRA's American Rifleman. He was testing LC Match brass in 30-06 and had accumulated a pretty good stokpile with grossly off-center flash holes. After testing for pressues, velocity and accuracy against other "perfect" cases from, the same maker, there was virtually no difference. Lot of energy in that little primer, and it'll find it's way through a flash hole whether it's right in front of the center of the anvil or not. No worries here.
     
  5. LRHWAL

    LRHWAL Well-Known Member

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    Hey Boomtube, no problem, I'll load them on Friday then! :D

    Guys thanks for the input, I was properly ticked off! I've never had trouble with WW before and as I said the following lot was fine.

    Feel much better now.... :D
     
  6. phorwath

    phorwath Well-Known Member

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    Thanks Kevin,

    I've always wondered about this, but never wanted to burn the time and money running any tests of my own.
     
  7. MNbogboy

    MNbogboy Well-Known Member

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    The flash hole is off center when the de-capping pin enlarges it.
    IMHO
     
  8. Bart B

    Bart B Well-Known Member

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    If that happens, one should use a smaller pin. But I find it hard to believe that using a pin too large will change the hole's center unless there's a big difference in brass hardness from one side of the hole to the other.

    Enlarging flash holes quite a bit is a guarantee to get higher pressures and probably higher muzzle velocity spreads. Some folks will use a drill bit one thousandth larger than the biggest hole in a lot of brass so they're all the same size. This is OK to do. I've done it but didn't see any difference in accuracy.
     
  9. MNbogboy

    MNbogboy Well-Known Member

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    Bart B,
    You are so right..What I meant and should have said is that "when the pin gouges the side of the flash hole and elongates it then it is "too" far off center for me....And when it is so far off that it bends the pin you will know for sure....I have seen a few lots of brass and several singles over the years where this has happened to me.....But as far as what the others have seen no measurable differences in accuracy because of off center flash holes....
    Randy
     
  10. MNbogboy

    MNbogboy Well-Known Member

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    Here is a brand new "off center"...Totally unusable....One only out of 100
     

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  11. Bart B

    Bart B Well-Known Member

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    Ain't in amazing that machines made and operated by humans make mistakes?

    I got a case of a thousand Federal nickle plated .308 Win. cases years ago, three of them had no flash holes at all.
     
  12. MNbogboy

    MNbogboy Well-Known Member

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    Ain't that the truth...My career is machine design and yep the machine as well as the human operating them make mistakes(including the machine designer)..If I didn't make mistakes I wouldn't have any reason to ask questions and would have been done learning a long time ago because it seems I learn best from my boo-boos...
    We are trusting our limbs, eyes and lives to our ammunition component makers so I hope giving them the benefit of the doubt when we run across one of their goof-ups is enough to keep them on their toes...It certainly should keep us as re-loaders awake and always a keen awareness looking for anything and everything that can go haywire....
    Randy
     
  13. SBruce

    SBruce Well-Known Member

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    WoW!!

    I've never seen one that bad, out of many thousands! Mostly Winchester though..??

    Reading this post makes me think back on reasons for loading with a powder that really fills the case as much a possible.

    Really, just an opinion; no scientific measurements to support, but I see slightly off center flash holes being a problem when the powder is laying on the low side of the case when fired. When the powder is packed full, it shouldn't matter as much.
     
  14. Bart B

    Bart B Well-Known Member

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    All the powder lays in the low side of the case when the chamber's horizontally oriented. Gravity always does that.

    If the powder density in the case is 100%, then chamber orientation doesn't matter. At any density less than that, there'll always be some space between the top of the case and the powder.

    But I don't think that even a case with only 80% powder density will show noticable difference in shot dispersion from flash hole's being anywhere from zero to 100% off center. But there is a difference between the powder's front to back orientation in the case; that's already been proven.

    Match grade ammo made in British and Australian cases with Berdan priming didn't seem to have any problems. Loading density was about 90% and both 2- and 3-vent hole versions were used. None of the locak top shots had any concerns about two or three primer flash vent holes all off center in the case head.
     
    Last edited: May 29, 2011