Questions for S1, brass preparation?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by 308, Jan 6, 2003.

  1. 308

    308 Well-Known Member

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    S1 I've enjoyed your information on this board very much. Hope one day to have a full custom long range rig put together and if I could do it now I would sure lean heavily towards a 30 wolf.
    What steps do you take in sorting and preping your brass for the 1/3 moa accuracy you get with your rifles?
    I have two semi custom rifles with min spec chambers, not tight necked but tighter than factory. They are a 6mm br with a pacnor 12 twist and a 308 with a schnider 12 twist.
    How much will turning case necks help accuracy in these non tight necked rifles, on average? I know individual rifles are a rule unto theirselves.
    And finally I have just got 200 Lapua cases for each of these rifles, What steps do I need to take to see the best performence out of this brass.
    Sorry for this being so long winded, If you would like to answer me at my email please feel free to: joey308w@yahoo.com Thank you for your time: Joey Sanders aka 308
     
  2. Guest

    Guest Guest

    Howdy 308

    It is true that each rifle is a unique story, we have great luck with non tightnecked chambers by only sizing 80 percent of the neck, and turning those necks. The comments below apply to Lapua and every other type of brass I have ever seen.

    I will list the stuff I do in the order of typical importance, grant me that lots of brass vary in quality on a number of points and your lot may have bad wall thickness consistency, where my lot may have poor depth consistency of primer pockets.

    Everything we do to a piece of brass affects at least one of these 3 things: concentricity, consistency, pressure curve.

    1) Uniform the DEPTH of the primer pocket.

    2) Turn the neck to a consistent wall thickness.

    3) Sort by weight and then by volume.

    4) Now sort by wall thickness variance on the case body .500" above the head.

    5) Ream the flash hole from the outside to the desired diameter, also centering it in the primer pocket.

    6) Fire form, trim to uniform length, and double check for weight variance, culling the few oddballs in weight after uniforming their length.

    7) Seat bullets with a low mechanical advantage press and cull any rounds that the neck tension does not feel identical.

    8) Spin rounds on a runout device to check for body to neck concentricity, and ogive to body concentricity.

    308- There are a couple of other important steps I will have to e-mail you.... I won't be able to post them until STL_Shooter comes down from his high horse.... [​IMG]

    Just kidding, that about covers it for us. [​IMG]

    [ 01-06-2003: Message edited by: S1 ]

    [ 01-06-2003: Message edited by: S1 ]
     
  3. ewallace

    ewallace Well-Known Member

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    S1
    What tool do you use for step 5?
    Crow mag
     
  4. Guest

    Guest Guest

    Crow Mag

    I will send you one to try, if you want. E-mail me with your address.
     
  5. Guest

    Guest Guest

    S1, do u make this tool or can it be found some were elese?
     
  6. 308

    308 Well-Known Member

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    S1 Thank you, That is the kind of information I was looking for.

    I too am interested in the tool you use for steps 4 and 5. Which tool do you use for step 4 and how much do you allow the body walls to vary. Thanks again, 308
     
  7. dbhostler

    dbhostler Well-Known Member

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    S1, maybe this should be another thread, but what do you do with bullets? Anything special with primers?
    db
     
  8. dbhostler

    dbhostler Well-Known Member

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    S1, maybe this should be another thread, but what do you do with bullets? Anything special with primers?
    db
     
  9. Guest

    Guest Guest

    Ohio Hunter and 308

    Yes I do make these tools, and so do a few other guys. We were talking about Hoehn a few weeks ago, because someone wanted the tool used in step 5, and he usually stocks them. I do not remember the thread, but will keep looking. If some one can remember please cough up ron's web site.

    The tool for step 4 is another matter, I have only made one of these fixtures, and would need quite a few orders to embark on making more. It is cool, and is fast to use, but a pain in the a_s to build. I sort on the body in .0015 increments.

    Anything greater than .003 I use for hunting at less than 1,400 yds. and pressure tests with new powders and bullets. Any brass greater than .0015 and less than .003 I use for Ultra long range hunting. The brass that is less than .0015" I reserve for things like DC's money. [​IMG]

    Call Ron at (636) 745-8144

    [ 01-06-2003: Message edited by: S1 ]

    [ 01-06-2003: Message edited by: S1 ]
     
  10. RedMist

    RedMist New Member

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  11. 308

    308 Well-Known Member

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    S1, since your case body wall thickness checker is a one of: What is your opinion of Neco's gauge for TIR and wall thickness checking?
    This information is virtually unobtainable elsewhere.
    Learning, Loading and Shooting: 308
     
  12. Brent

    Brent Well-Known Member

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    S1,

    Few questions:

    - If the cases have identical internal case capacity wieghed with water, what does the thickness matter at .5" above the head?

    - Is it an accuracy issue or is it one of case life?

    - Variation tolerance of .0015" and distance of .5" above head, how do you arrive at these specific figures? Tell us something that supports this being worth while? If you have said somewhere, I missed it. Thanks.

    The other steps, I follow you on. [​IMG]
     
  13. Guest

    Guest Guest

    Howdy Brent

    The case wall thickness issue does not affect pressure in a significant way that I know of. The reason we measure it is because we resize the case, and care about concentricity. Any time you resize with different wall thickness you move the thin side more than the thick side, which allows the case to misalign with the neck, not good.

    I don't know if there is a small affect on case life, I have not noticed it if there is.

    The wall of a case tapers thinner the closer you get to the neck. We have found that if you measure too close to the bottom you can be fooled, and too high there is not as much variance to measure, thus .500 above the bottom of the inside of the powder column or end of the flash hole works well with Lapua cases.

    It is truly an accuracy issue, concentricity affects accuracy, whether or not it is worth it is up to you and your style of shooting. [​IMG]
     
  14. Guest

    Guest Guest

    dbhostler

    I do several things with bullets when I am working or competing.

    Measure the ogive to base and make sure it is within .001"

    Inspect the rear of the bullet and cull anything with scratches, dents or other abnormalities.

    Cull any bullet with a large meplat or odd overall length.

    Mic the O.D. where the major diameter meets the boat tail.

    Dynamically spin, and cull anything with an unacceptable CG offset.

    This procedure will allow boat tail bullets to group under .140" five shots in a tunnel at 100 yds. in a very good rifle. [​IMG]

    The bad news is, I have to carry a mirror with me so I have someone to blame when I miss. [​IMG]