How to reduce bullet runout?

Discussion in 'Reloading' started by zoeper, Oct 26, 2008.

  1. zoeper

    zoeper Well-Known Member

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    I loaded up some 6mm berger 88gr high bc's for the 243 today and made a tool to measure bullet runout. I was amazed to find that i'm getting up to 12 thou runout near the tip.

    Some of the things i noticed:
    1. due to the sharp profile of the bullet, the seating plug does not touch it on the ogive, but the tip of the bullet sticks through the hole in the seating plug, causing the edge of the hole to be the only contact with the bullet, leaving a ring near the tip of the bullet. (standard lee seating die)
    2. I'm getting quite a bit of runout on the case neck after bumping shoulders back with the lee full length sizing die.
    3. i was trying to get into the lands, but due to the sharp profile, i cannot get into the lands and still fit into the magazine. At 74.9mm COAL i feed properly and seat 2/3 calibre into the neck without touching the lands. (i would have liked to get at least a calibre depth into the case neck, but that would take me miles off the lands.

    I am not doing benchrest with this setup, but i need to get MOA accuracy or better without breaking the bank (bank's already broken:()

    Would it help to straighten them out after loading?

    Any advice much apreciated.
    P
     
  2. kraky2

    kraky2 Well-Known Member

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    You can get MOA out of even basic lee dies.

    Don't measure runnout near the tip....measure it about 1/2 way between the case mouth and the ogive of the bullet.
    Sounds like the seater is actually working fine. When it pushes on the very tip of the bullet it gets hard to seat straight.
    You need to get your die to make straighter cases during sizing. Most likely the expander ball is pulling the neck off center.
    You need to get that expander ball centered better in the die. On a lee die the first thing I do is turn the lock ring upside down so the funky O-ring is out of play. Then you need to fiddle with the expander stem till it is centered. If I remember the lee die has a lock nut on top that crimps or holds the stem in place. Try loosening it slightly and bringing a piece of brass up to the expander ball to hold it centered then tighten the nut. Try sizing 5 pieces of brass and see if it improved. If not you may have to keep loosening and tightening till you get the stem centered. Eventually I think you'll find a sweetspot where it is centered. Early hornady dies locked the expander like the lees and I've loosened and tightened a number of the hornady's until I got them making really great runnout. It sounds crazy but if you get an expander centered well they can make match grade ammo and certainly ammo that can go moa. BTW--if your gun is up to it and likes your load ammo with .005" runnout and under can easily go moa.
     

  3. boomtube

    boomtube Well-Known Member

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    "2. I'm getting quite a bit of runout on the case neck after bumping shoulders back with the lee full length sizing die."

    Low run-out with bottle neck cases depends almost entirely on straight necks and that means both good brass and excallant sizing/expanding methods. ALL conventonal expander buttons tend to pull necks out of line but Lee's long expander section is perhaps one of the best conventional types.

    For factory rifles, light neck turning can help but don't bother cutting more than about 75% of the neck circumference if you do it. We can turn a perfectly concentric neck that is such a lousy fit in the chamber it may well be worse for accuracy, not better.

    With carefully selected and lightly neck turned brass, I prefer to FL size with a body die which doesn't touch the neck at all. Then I usually use a Lee Collet neck sizer die because it makes the straightest necks I've been able to produce. If I'm neck sizing with the Lee die alone, and I often do, I dispense with the body die.

    IF I have to use a conventional FL sizer, I first decap with a universal decapper and remove the expander/decap rod from my FL sizer. After sizing, I use a Lyman "M" expander die which works by pushing IN rather than pulling OUT and that makes necks almost as straight, on average, as the Lee Collet neck sizer.

    We may measure run-out any way we choose but I disagree with Kranky's method only because it will automatically give lower readings than the bullets actual, full length tilt.

    I prefer to measure bullet run-out as near the tip as possible so I can to see the maximum difference possible. That way I can more easily gage the results when I change methods or tools. When my cartridges read .002" or less TIR, I know I have some straight ammo! (Total Indicated Run-out is twice the actual tilt of the bullets.)

    Can we bend the bullets to improve run-out? Sure. If the seating depth is slight it may even help accuracy. But, if the bullet is seated deep, I fear we may get a "straighter" round at the expense of some degree of compression damage to the bullet's thin jacket and soft core. I prefer to work on my cases, loading tools and methods for straighter ammo rather than bending them straight.

    Good luck.
     
    Last edited: Oct 26, 2008
  4. zoeper

    zoeper Well-Known Member

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    Boomtube, there is a lot of meat in your response and i will investigate your methods. I just used the suspect rounds this morning without messing with them any further. at least now i am back to fire formed cases and i can start by measuring after every step in the process to see how the runout devellops during the whole process.
    I will post my findings.

    Thanks
    P
     
  5. Limbic

    Limbic Well-Known Member

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    Don't the Lee's collet neck dies help with this problem?
    Shoot it and then just resize the neck.

    I'm really asking, not implying that I know.
     
  6. boomtube

    boomtube Well-Known Member

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    Yeah, it does. Perhaps it's use is the most important single tool I've used for straighter necks. But, there is a lot more that can be done to get run-out averages down to the lowest possible numbers.

    A good seater helps quite a bit too. Seaters by Forster (my choice) or Redding won't make case necks any straighter but they sure won't add any run-out to good cases. Their expensive micrometer seating heads add nothing to concentricity but they do make it easy to do small seating adjustments when the right seating depth is known.
     
    Last edited: Oct 27, 2008
  7. Boss Hoss

    Boss Hoss Well-Known Member

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    I know this is going to ruffle a few feathers but it cannot be helped. First everything starts with the sizing operation think of it as a foundation of a house. Make sure the sizing die is centered when installing it in the press then ensure that each round has the right amount of lube otherwise you will have inconsistent sizing of the brass and that is very bad juju for accuracy. All of my Wilson sizing dies are cut with the finish reamer that was used to chamber the rifle but in your case this will be impossible to do so just order the Wilson seating die and an arbor press (forget about using a conventional press).

    It is much easier to find the systemic cause of your problems rather than try and correct after the fact but this device will help you do both Concentricity Gauge . In the former you can check your concentricity and the later will enable you to correct it if needed. I am a 1k BR shooter and like to win because losing sucks but that being said your accuracy problems might be helped by this and then again it may not make any difference at all. This will be however, another step in the right direction to achieve smaller groups and bring out the accuracy potential of the rifle.
     
  8. zoeper

    zoeper Well-Known Member

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    "just order the Wilson seating die and an arbor press (forget about using a conventional press)."

    What is the difference between an Arbor and a conventional press and what makes one better than the other?
    P
     
  9. Winchester 69

    Winchester 69 Well-Known Member

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    Were these loaded on the defective press you have previously commented on?
    .
     
  10. Guy M

    Guy M Well-Known Member

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    Arbor press, Wilson dies:
    [​IMG]

    Sizing:
    [​IMG]

    [​IMG]

    [​IMG]

    Bullet seating:
    [​IMG]

    [​IMG]

    I use the arbor press (mine is a Hart) and Wilson BR type dies to load my .308, .25-06 and .204 Ruger ammo. It's an interesting way to load, and produces extremely accurate ammo.

    Regards, Guy
     
  11. boomtube

    boomtube Well-Known Member

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    BR reloading methods are great. For BR rifles. Usually, costing from $2K up. Such methods and tools have little or no value for factory rifles tho. And, for Zoepers request to help him achieve MOA or better, that's a bit of over kill.

    An arbor press is a simple divise having a short overhead ram that pushes the case and dies together without use of a shell holder to withdraw it. The press is not threaded so there is no point in threading the dies. These tools avoid any potential misalignment between the dies and press that may be found in a conventional setup.

    As one poster said, the dies are best if cut with the same reamers that cut the chamber. The dies usually get cut with the "roughing" reamer which is slightly smaller than the "finishing" reamer used on the rifle itself.

    Using all the BR methods and devices may cut 1/8" of an inch off a good rifle's groups with well made ammo. That's lot in BR competition but it doesn't mean much to many hunters, it only changes the radius of error by 1/16" MOA! Using good sizing and seating methods with more conventional dies and presses seems more reasonable for most of us and is much more in keeping with Zoeper's goal of obtaining MOA with his .243 without breaking the bank.
     
    Last edited: Oct 27, 2008
  12. Guy M

    Guy M Well-Known Member

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    Agree - and he asked, so I showed him my Arbor press setup. It did make a difference in the quality of my .308 long range loads.

    I still load most of my hunting ammo with my good ol' RCBS Rockchucker and RCBS dies. Do like the "New Dimension" Hornady dies for my .300 WSM though!
     
  13. Boss Hoss

    Boss Hoss Well-Known Member

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    Please provide the backup data that supports your analysis as I am curious how you quantified your conclusions. I hear this all of the time and in the end it is usually based on assumptions and "something somebody heard from someone else" not actual testing and fact finding by the poster.


    The poster asked a question about a specific subject and deserves an informative answer based on actual hands on knowledge of the subject imho.
     
  14. boomtube

    boomtube Well-Known Member

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    Boss Hoss - "Please provide the backup data that supports your analysis as I am curious how you quantified your conclusions. I hear this all of the time and in the end it is usually based on assumptions and "something somebody heard from someone" else not actual testing and fact finding by the poster."

    There are several statements in my post and I have no idea what statements or conclusions your question is related to.
    Do you have any actual test data, or even assumptions, contridicting one or more of my statements? If so, don't just ask an open ended question, please tell me/us specifically what you find absent, misleading or wrong in my post.
    ---------------------------------------------------------

    Guy M - "Agree - and he asked, so I showed him my Arbor press setup. It did make a difference in the quality of my .308 long range loads."

    No contest. I worded it poorly but not meant as a negative reflection on your post at all, just wanted the OP to understand where your neat BR setup fits into the big picture and even to expand a little on the excellant photos.

    How much difference did your BR gear make in your LR accuracy, and was it fired from a common factory rifle?
     
    Last edited: Oct 27, 2008