Case Neck Thickness Variation

Discussion in 'Reloading' started by bill123, Mar 10, 2014.

  1. bill123

    bill123 Well-Known Member

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    I know this has been touched on in many threads but I can't seen to find an answer that directly relates to my question:

    I'm sorting brass by neck variation to get more consistent groups for 1000 yard. I'm trying to avoid turning. What is tolerable inconsistency in a neck?

    My Lapua 308 brass runs from .0145" -.017".
    50% of it is .015"-.016" within a case.
    I have some running .015"-.0155" and some .0155"-.016.
    There are very few cases that run .0145"-.015" or .016"-.017".

    Any suggestions?
     
  2. Mikecr

    Mikecr Well-Known Member

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    You didn't say your chamber neck diameter.
    Personally, I cull anything outside .0005 total variance around necks, and covering desired thickness(whether turning or not). I do this to reduce runout down the road, and to ensure I'm not overworking necks in sizing, and to match my brass in H20 capacity.

    Your variance spread is higher than normal though.
    What are you measuring with?
     

  3. bill123

    bill123 Well-Known Member

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    Fired case: .340”-.341”
    Finished Lapua cartridge w/ bullet: .337”-.338”
    Using a Redding Case Neck Gauge. There is a bit of slop in it.
     
  4. Mikecr

    Mikecr Well-Known Member

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    This is why you're getting so much variance..
    You need a neck micrometer with a stop.
     
  5. bill123

    bill123 Well-Known Member

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    When I say slop I'm talking maybe 1-2 ten thousandths. What is the Redding tool used for?
     
  6. jfseaman

    jfseaman Well-Known Member

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    Turn em all to .0145
     
  7. bill123

    bill123 Well-Known Member

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    I was hoping to avoid turning by sorting and shooting like batches. Anyone use that strategy?
     
  8. Canadian Bushman

    Canadian Bushman Well-Known Member

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    Thats what i would do
     
  9. bill123

    bill123 Well-Known Member

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    About how long would it take you to turn 200 cases from say .0165" to .0145"?
     
  10. Canadian Bushman

    Canadian Bushman Well-Known Member

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    I turned, trimmed, and chamfered 300 lapua cases in about 4 hours not too long ago.
     
  11. bill123

    bill123 Well-Known Member

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    Assuming you would have the desired thickness left, would you turn cases with only .0005" variance?
     
  12. flashhole

    flashhole Well-Known Member

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    If you are tooling up to turn them, turn all of them.
     
  13. jrock

    jrock Well-Known Member

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    I sat on the sideline trying just what you are doing and eventually tooled up for neck turning. I also have a Redding neck thickness gauge but I ordered a 0.0005" dial gauge for it and get all my cases under 0.0005". If you want to be serious about it, I would recommend a micrometer. I shoot factor chambers and neck turning makes a difference in my guns. Once you get everything set up, it isn't as bad as everyone makes it out to be.
     
  14. bill123

    bill123 Well-Known Member

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    What's the dial gauge for the redding tool?