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neck thickness variance

Discussion in 'Ammunition & Reloading' started by prkrgrp, Apr 2, 2011.

  1. prkrgrp

    prkrgrp oregon Active Member

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    i am starting to notice neck thickness variance
    will a neck die correct the problem or do i need to trim the neck brass?
    thanks
     
  2. evltwn

    evltwn Gold Hill Oregon Bronze Supporter Bronze Supporter

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    To quote pg 53, Lyman's 49th edition, "Generally, your loaded round neck diameter will be well below the maximum. Should case neck diameter begin to get close to the maximum, it is evidence of heavy brass flow from the case body. The wise reloader will then discard the entire lot of brass."
     
  3. prkrgrp

    prkrgrp oregon Active Member

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    i am referring to the brass thickness at the neck, this is once fired brass min loads. one side of the neck is 5 thousands larger than the opposite side
     
  4. jib

    jib Central OR Active Member

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    "i am referring to the brass thickness at the neck, this is once fired brass min loads. one side of the neck is 5 thousands larger than the opposite side"

    I discard such brass, the wall thickness variation likely runs through the entire case.
    Of 100 Federal .308 Win. cases I may keep 60% of them.
    You get what you pay for, spending extra will save time, with less headaches.
     
  5. jer fly

    jer fly cottage grove Member

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    Jib is right. if your case neck is thicker on one side it is likely through out the entire case. After resizing, turning the outside of your case will uniform the neck thickness, but does nothing for the rest of the case. Depending on your application, I would see how well they shoot in your specific rifle. If accuracy is acceptable go with it... If not you might want to try sorting brass ( if you have a lot already ) or just buying some quality stuff like lapua, hornady, or nosler.
     
  6. Spitpatch

    Spitpatch Forest Grove, Oregon Well-Known Member

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    And a double-ditto. The brass is probably variable thickness from the head to the neck. Outside neck turning should only be necessary on brass that has been necked down to the desired bullet diameter from a bigger caliber. (Or, for benchrest-quality handloading). Neck release (meaning the neck is letting go of the bullet as it should, rather than being hampered by its thickness against the chamber wall) can easily be checked by taking a freshly fired case, and fitting it over a bullet in a loaded cartridge (or seeing if a bullet alone drops inside easily). If the fired neck does not fit a bullet somewhat loosely, neck release is insufficient: a source of some pressure increase.

    Brass with eccentric thickness in the neck can result in minor misalignment of the bullet to the bore. For garden-variety AR blasting, this should not be much of an issue if sufficient neck release is happening. For fine-tuning accuracy handloads it is definitely something to consider. Inside neck turning is not an effort I would waste on low-quality brass.
     
  7. deadshot2

    deadshot2 NW Quadrant WA State Well-Known Member

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    I neck turn all my brass after it is shot once. This evens out the thickness and I don't find this condition again as long as I keep the brass. Neck turning also gives a more uniform neck tension if all cases in a group have the same thickness from round to round.

    Since I don't have a custom chamber and don't have a specific dimension to maintain, I merely set my neck turning tool to "even out" or as some have said, "knock off the bumps". The results are great. With a Factory Stock Rifle I have consistently shot groups of less than 1/4" at 100 yards with similar results out to 300 yards.