Bushing Die Expander Ball

Discussion in 'Main Message Board' started by Justin Schuerg, May 16, 2019.

  1. Justin Schuerg

    Justin Schuerg

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    I've got a question about whether to use an expander ball with a bushing die or not. I am in the process of working up a load for a 6.5 PRC. I've got an RCBS Gold Match bushing die. I have been doing a lot of reading on bushing dies and trying to fully understand the advantages/disadvantages of using one and also if it is intended to be used with the expander ball or not. My understanding is that most expander balls are sized .001" smaller than the bullet diameter, which in my
    case (using a .264 bullet) would be .263". Sooo below are two examples of cases with different
    case neck thicknesses which I am going to calculate the bushing size for (-.001")

    Case 1 (.015" neck thickness)
    Bushing Size = (.015 + .015 + .264) - .001 = .293
    Case Inside Diameter = .293 - .015 - .015 = .263 inside diameter

    Case 2 (.013" neck thickness)
    Bushing Size = (.013 + .013 + .264) - .001 = .289
    Case Inside Diameter = .289 - .013 - .013 = .263 inside diameter

    In every scenario if you are sizing the bushing .001 less the inside diameter of the case ends up
    being .263 which is, from my understanding, what most expander balls are (.001 less than the bullet). Am I looking at this correctly? If I am I don't see the advantage in using the expander ball.

    Thanks in advance for any feedback....
     
  2. butchlambert

    butchlambert Site $$ Sponsor

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    I have never used an expander ball on my bushing dies. I have a set of 9 sizes of carbide bushings in .0005 increments for each caliber that I shoot in competition. The expander is superfluous.
     
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  3. rgc54

    rgc54 Silver $$ Contributor

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    You would just be overworking the brass if the expander even did anything at all
     
  4. Justin Schuerg

    Justin Schuerg

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    I agree, but since the diameters are technically the same I would think it would just barely rub the inside of the case coming out. My thought is why not leave the expander in just in case the
    mouth of the case had a ding I didn't know about.
     
  5. antelopedundee

    antelopedundee

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    If you can select any size bushing that you want then why even bother with an expander? Especially the junkie ones that come with standard dies. My understanding is that those ball type expanders are largely responsible for crooked case necks. So I would suggest for an expander that you use a mandrel that would be the same size as the one you will be using to turn your case necks. So after turning necks [and probably the first firing] you size your cases with the appropriate bushing and separately expand them with the mandrel/expander. For me I wouldn't expand at all, but that's what I would do and may not be what you would do. Also it's nice to calculate sizes, etc. but if your brass is springy and doesn't resize properly, you'd need a different bushing.
     
  6. Justin Schuerg

    Justin Schuerg

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    I appreciate the feedback. That's what I'm looking for. I've always used standard FL dies and this is my first go with bushing dies. I was pretty confused because I've read so many different opinions on whether or not to use the expander ball. I was actually sizing some new brass and had the expander in just to clean up any dings from shipping. I noticed that when I pulled the
    case back through the expander ball it barely rubbed the side of the case. I check the concentricity on the cases and they were no more than .001" so thats what got me wondering if there was any benefit from removing it...
     
  7. jepp2

    jepp2 Gold $$ Contributor

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    I don't know exactly what type of "ding" you are envisioning. But what I find, is the compressing action of sizing the die neck (bushing or standard die), really makes everything round again.

    And from my actual measurements, I can tell you that if the expander is having to open up the case neck 0.002" or more, it will pull the neck off center. Even with lube and a carbide expander. And if you measure the reduction of case neck during sizing in most FL sizer dies, they seriously undersize the case neck. And that poor expander has to make it right.

    Store your expander in the die box.
     
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  8. Dusty Stevens

    Dusty Stevens COVFEFE- Thread Derail Crew Gold $$ Contributor

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    With a fixed expander a bushing die is kinda useless. It drags back thru the neck and makes it the same size no matter what bushing you use
     
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  9. Uthink Uknow

    Uthink Uknow Gold $$ Contributor

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    Bounce that ball into the trash.
     
  10. nvtoy

    nvtoy

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    Question, wouldn’t the bushing push the flaws to the inside of the case? Course that’s with non neck turned cases. With the bullet seated these flaws might effect concentricity and bullet run out. With a proper fitted expander lightly ironing out flaws to outside of case could this be better?
     
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  11. Barlow

    Barlow Silver $$ Contributor

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    If it were me I would leave that as is. Barlow
     
  12. butchlambert

    butchlambert Site $$ Sponsor

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    No sir, that is a wet dream. I have some custom reamers for the inside of my necks. It ain't worth the time.
    The only reason to worry about this is to find an excuse for poor shooting. The most important thing you can do to improve your shooting is throw a lot of bullets down range while learning to read your windflags.
     
  13. antelopedundee

    antelopedundee

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    The bushing/sizing die creates a case that is round on the outside. Using an expander or bullet pushes any flaws like uneven wall thickness back to the outside. With a competition type seater die these flaws may be minimal if case neck thickness isn't all that much non-uniform.

    OTOH some commercial ammo can shoot pretty well so you have to consider how much all of your tinkering will help. If done right it can't hurt.
     
  14. antelopedundee

    antelopedundee

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    As an aside, I would ask if .001 neck tension is a puny amount. Wouldn't you want more to give the powder a little more time to burn, especially for hunting ammo?
     
  15. antelopedundee

    antelopedundee

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    Are you equating neck wall thickness with runout? .001 variation in neck wall thickness for new commercial brass is pretty darn good IMO.
     
  16. 243winxb

    243winxb

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    Shoot 4- 5 shot groups each. With and without expander. Then we will all know when you report back.:)

    When no expander is used, the bullet becomes the expander.
     
  17. antelopedundee

    antelopedundee

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    Even flat base bullets have enough bevel that they will seat into tighter necks without issue.
     
  18. Justin Schuerg

    Justin Schuerg

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    That's an obvious point I didn't take into consideration. When no expander is used, the bullet becomes the expander. My original question was since the expander ball and
    inside diameter of the case (after sizing with a bushing) are pretty much the same why not leave the expander just in case you had a case neck that was a little dented that you didn't
    know about. I was thinking in that scenario the expander ball would take care of it, but the bullet would do the same so I quess the expander wouldn't provide any benefit.
     
  19. antelopedundee

    antelopedundee

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    I've made that same point here and elsewhere. It depends upon if you want THAT much neck tension aka bullet pull. IMO the more the better unless you seat your bullets to touch the lands. Many consider the expander ball that comes with the dies as junk. Apparently the die makers don't agree. You can also get them tapered or football shaped. If you wish to size and re-expand I would suggest the Sinclair Generation II expander die. There is also offered steel and carbide mandrels. For example in 6.5mm they have both .262 and .263 mandrels.

    If you use the Redding competition seater dies they advise against not expanding the necks [along with compressed loads] when seating bullets.

    https://redding-reloading.com/tech-line-a-tips-faqs/168-working-with-your-competition-seating-die

    From the link. Intended for compressed loads, but applies to tight necks also I'm told.

    "To hold the bullet concentrically, the Bullet Alignment Bore and the Seating Stem have been honed and ground to virtually the same diameter as a jacketed bullet. As a result, the seating stem walls are relatively thin and not as inherently robust as the Seating Plug in a standard Seating Die. Though the Stem is heat treated to make it as strong as possible, it will not endure the excess seating pressure of Compressed Charges. This excess seating pressure will crack the Seating Stem which will, in turn, damage the other internal parts of the Die. Please be mindful because replacement parts are costly and NOT covered under Warranty. Please remember that your Competition Seating Die is a precision instrument and should be used and treated as such. A handloader using this Die to compress powder is tantamount to a machinist using a Micrometer as a C-Clamp."
     
  20. Justin Schuerg

    Justin Schuerg

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    So your saying that you believe more neck tension is better?
     

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