Neck turning?? Hurt accuracy?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Goobie270, Jun 3, 2018.

  1. Goobie270

    Goobie270 Well-Known Member

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    I'm thinking of neck turning my brass or just cleaning up about 80% of the neck. Can doing this ever hurt accuracy where I should have left the cases alone?
     
  2. elkaholic

    elkaholic Well-Known Member

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    It shouldn't hurt. Excessive clearance COULD affect accuracy but just skinning it should help if your equipment is consistent and you end up with uniform thickness.
     
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  3. Goobie270

    Goobie270 Well-Known Member

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    Ok thanks, I just didn't want to hurt or ruin my lapua brass. I should have said it's for a factory rem 308 5r. I just thought I could clean up and make the brass uniform, and didn't want to hinder accuracy.
     
  4. elkaholic

    elkaholic Well-Known Member

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    Lapua brass is normally pretty true to begin with but skinning it carefully should be ok. Try to remove enough so that they are all the same without over doing it. On Lapua, 1/2 thou might do it
     
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  5. Goobie270

    Goobie270 Well-Known Member

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    Ok thanks elk.
     
  6. elkaholic

    elkaholic Well-Known Member

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    You bet.
    I usually meaure the neck o d on a fired case and then size and stick a bullet in a couple samples of your brass and check the o d again. If the difference in the measurements is .002" or less, you definitely need to remove some brass. If the difference is .006" or more, you'd better leave it alone, or a VERY light skin. I personally like approx. .004-.005" clearance. Keep in mind that when you measure a fired case, it will likely be .001" or so smaller than your chamber because of spring back.
     
    Last edited: Jun 3, 2018
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  7. Mikecr

    Mikecr Well-Known Member

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    All that's needed to know neck clearance is a simple measure of necks after firing. As mentioned, the chamber neck is ~1thou over this measure, as the brass sprung back from it. This is with normal brass that is not over annealed.
    And even with little clearance(like 2thou), you do not have to neck turn for this. Clearance is clearance.

    I don't know if you want to turn for low runout, or for lower neck tension, or both. Which is it?
     
  8. AZShooter

    AZShooter Well-Known Member

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    As others have said Lapua brass is pretty consistent already. I doubt you will see any difference in performance by skim turning the necks of this brand of brass and your factory rifle. If you take off too much with that SAMMI chamber the brass will be overworked and it will cause neck splitting. (I know it did it) If you don't have the equipment to turn the necks AND dies to properly size the necks afterwards, you will spend money and time and might not see any improvement.

    If you do try turning some necks please do a control with some unturned brass and for a comparison. When you are done testing please share this information with us.
     
  9. Goobie270

    Goobie270 Well-Known Member

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    I wanted to turn necks for run out. Just to make the neck uniform.
     
  10. Goobie270

    Goobie270 Well-Known Member

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    Ok thanks everyone for the help, if I decide to turn a few I will share my results.
     
  11. Varmint Hunter

    Varmint Hunter Well-Known Member

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    I'd measure a few necks for uniformity with an appropriate gauge. My guess is that you will find no need to turn the Lapua necks.
     
  12. J E Custom

    J E Custom Well-Known Member

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    All good information.

    The main reason I turn the necks is to uniform them so they will have less concentricity and more uniform bullet neck tension consistency. I prefer to turn the necks while the brass is new so firing it will true it up.

    Different brands may require more or less turning and as long as you don't over do it, it can only help. Some brass have thick necks (Like the military) and need turning to better fit the neck chamber.

    J E CUSTOM
     
  13. elkaholic

    elkaholic Well-Known Member

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    The reason I mentioned less than .002" clearance requires a little brass removal is because, in most instances, for most people, it's a smart thing to do. Yes, .002" is sufficient clearance if you have that every time. The problem is it leaves very little room for error. Especially in hunting ammo, it's easy to get a little debris in the chamber which can cause Issues. Also, except on rare occasion, I have found that .004-005" gives lower es and better long range accuracy.
    It is highly unlikely that in a factory chamber, shooting Lapua brass that this would ever be a problem, but that is the rationale behind clearance, or lack of....rich
     
  14. Goobie270

    Goobie270 Well-Known Member

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    Ok I measured a couple fired rounds and a couple loaded rounds and the difference is .004 to .007. I tried cleaning up the neck on a lapua brass and there is a fair bit on one side. So I'm hoping if I just clean them up to a uniform thickness all the way around the neck it won't hurt accuracy
     
    Last edited: Jun 4, 2018