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Thread: Case Length Uniformity

  1. #1
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    Default Case Length Uniformity

    Gentlemen, and Fellow Rascals:

    Here's a handloading question, that I've been wondering about recently.

    Let me preface, by saying.....

    Granted, case lengths should be the same in any batch of of loaded rounds, to help keep the neck tension uniform.

    It is especially important to have case lengths all the same if you are crimping, so the Crimps are uniform.

    Now, the question...?????

    Just how close do they have to be in length? (For Crimped Rounds), ( in .xxx )
    Are we talking about .002, .004, .007, .010, for example?? My own theory is that several thou. diff is OK.

    I've noticed that even when I trim all cases with the same setting of my Forster Case Trimmer, there is some variance in their lengths.

    Thanks for your thoughts, or experiences regarding this.

    Smitty of the North
    Walk Slow, and Drink a Lotta Water.
    Has it ever occurred to you, that Nothing ever occurs to God? Adrien Rodgers.
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  2. #2
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    Default

    Quote Originally Posted by Smitty of the North View Post
    Gentlemen, and Fellow Rascals:

    Here's a handloading question, that I've been wondering about recently.

    Let me preface, by saying.....

    Granted, case lengths should be the same in any batch of of loaded rounds, to help keep the neck tension uniform.

    It is especially important to have case lengths all the same if you are crimping, so the Crimps are uniform.

    Now, the question...?????

    Just how close do they have to be in length? (For Crimped Rounds), ( in .xxx )
    Are we talking about .002, .004, .007, .010, for example?? My own theory is that several thou. diff is OK.

    I've noticed that even when I trim all cases with the same setting of my Forster Case Trimmer, there is some variance in their lengths.

    Thanks for your thoughts, or experiences regarding this.

    Smitty of the North
    This is because the base is not quite perpendicular to the centerline of the case.
    If you want perfectly uniform case lengths (and I do), you need a C-H case trimmer. www.ch4d.com

    You insert the case into a holder that is milled to the shape of the case itself. I use mine on every cartridge I shoot.
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  3. #3
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    If we are crimping I think case length should be no more than .002" difference and that is about the easy limit of most trimmers. Some will cut to more uniform length but even the CH4D or the modern version of it, the Wilson trimmer, will vary one or two thou. If you are not crimping and case are within .004 or .005" of each other I don't think you could see a difference in accuracy. If bench rest shooting or other disciplines that require the utmost of precision then get the best equipment and learn to use it. Brass prep is a very important step. Remember the accuracy of a dial caliper, even a good one is +/- .001" and uniformity of technique in use can account for another .001".
    Is there nothing so sacred on this earth that you aren't willing to kill or die for?



  4. #4
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    Default

    I use a Redding 2400 with micrometer, and will accept nothing less than .002 variation, and that is on the extreme end. I'm less concerned with absolute variation, rather lots of variation (5-8 cases) If after I resize, and have 5-8 rounds that are precisely the same, and they are not too long, I'll leave them alone, since they will group the same. I only trim out the extreme variations to the nearest lot that I have to keep a uniform group. I've found that case weight has as much do do with consistent grouping as case length.

    It may be overkill, but I sort by weight first, then trim to uniform case length, then sort again by weight, as the act of weighing takes less time than measuring length.

    I have several zip lock baggies with various weights, but all the same length (for a given weight) that I keep separate.

    This method works primarily in low volume applications, as I don't shoot more than 3-5 rounds each of my 30-06.

    With the .223 however, I'm a lot more anal. I measure, in lots of 100, the shortest case length, extreme variations aside (i'll just set it aside or throw it away). Then I trim all to lowest case length nearest .001. I then weigh each case and separate to nearest .1 gr. If I don't have more than 20-30 of the same weight, I'll either wait until I have more to make a batch, or open another bag of unfired to find enough to make a lot.

    Call it excessive anal rententivity, but it's also a hobby, and I don't feel bad if it takes several hours as it is thereapeutic.

  5. #5
    Member marshall's Avatar
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    AKHELOCE,

    I started to respond twice and erased both times. I couldn't think of anything nice to say then I saw your response, perfect!

    If your going to reload then why settle for crap tolerances. We do this to achieve better than store bought ammo, right? I take it one step further and actually true my ammo. Why, because I want it to be as good as it can be.

    If your in it for economy then why trim or weigh your powder or sort your brass at all?

  6. #6
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    Thanks everbudby.

    Murphy:
    I was hoping you would weigh in on this.
    You're very through.
    Thanks

    Smitty of the North
    Walk Slow, and Drink a Lotta Water.
    Has it ever occurred to you, that Nothing ever occurs to God? Adrien Rodgers.
    You can't out-give God.

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