Help Me Understand Full-Length/with Bushing Resizing

Discussion in 'Reloading Forum (All Calibers)' started by South Pender, Mar 18, 2019.

  1. South Pender

    South Pender

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    This is probably too basic a question, but if someone would like to explain this, I'd be grateful. Back in the day when I began precision shooting, the standard resizing procedure was too neck-only resize with a bushing. I've used many L.E. Wilson dies to do this. The theory was that you were keeping the body of the case close to the chamber dimensions--not unnecessarily reducing it--while getting the neck diameter where you want it.

    I haven't kept up with the new thinking in this area and have only returned to precision centerfire shooting in the last several years, but it now seems that the favored approach is to full-length resize with a bushing (although some don't use the bushing). I don't really understand the advantages of doing this over simply neck-sizing. If I'm visualizing this correctly, this process would first expand the neck with the button while sizing down the body of the case. The case neck would then be reduced by the bushing. Then on removing the case from the die, wouldn't the neck be expanded again as it passed through the button? I guess I'm missing something here because this seems like a real re-working of the neck brass, with the bushing not really accomplishing its mission. Obviously, I've got this wrong. Can someone straighten me out? And what are the advantages of the full-length sizing of the case body over simply neck-sizing (as long as the rounds are going back into the same rifle each time)?:confused:

    Thanks in advance for your insights!
     
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  2. TrxR

    TrxR

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    I dont think many of them are using the expander button. Also i think they are setting the die to just bump the shoulder back a thou or so . That keeps everything consistent between firings and never the chance of a round being tight to close the bolt on.
     
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  3. rkittine

    rkittine Gold $$ Contributor

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    I too started reloading in the 60s with the understanding that the first firing got your brass to your chamber dimensions and then just neck size, though I never used an expander button even in those days. Now I full length size and slightly bump back the shoulder as stated above. BUT all my rifles these days have customer chamberings. Different than factory rifles chambered so that about any "standard" ammo in that caliber will fit the chamber.

    Bob
     
    Last edited: Mar 18, 2019
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  4. Uncle Ed

    Uncle Ed

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    The main reason so many shooters use a body die and a Lee collet neck sizing die is because they get less bullet runout than using a bushing die. That being said bushing dies work best with custom tight neck chambers with neck turned brass.

    So it depends on how much the neck expands when fired and how much the neck is reduced using a bushing die. The Redding bushing die FAQ tells you that you will induce neck runout when reducing the neck diameter .004 or more.
     
  5. _Raining

    _Raining

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  6. South Pender

    South Pender

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    So do you use two dies in this process--one to full length size the case, (with presumably the expander ball removed) and a second die (the Lee collet neck-sizer to resize just the neck)? How do you keep the full-length sizing die from sizing down the neck?

    I assume that the Lee collet die has the mandrel diameter .002"-.003" less than the bullet diameter. Can you count on the neck tension you want with this system--i.e., with no way to modify the reduction in neck diameter? Wouldn't you be better off with the flexibility that bushings provide?
     
  7. Dusty Stevens

    Dusty Stevens COVFEFE- Thread Derail Crew

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    Unless you were shooting for just a couple of years back in the 50’s neck sizing has never been in favor in competition shooting. That is a myth that we just cant get rid of for whatever reason.
     
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  8. K22

    K22

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    Like many who started reloading in the 60's, I believed that neck sizing provided longer case life and improved accuracy because that's what the "experts" claimed in gun magazines. It wasn't until I started getting rounds that wouldn't chamber or extract that I began to rethink neck sizing. I sought help from a precision rifle shooter who shot very tiny groups and he educated me which resulted in changing my sizing method.

    The key to properly full length sizing is to only push the shoulder back about .001 to .002" (bolt rifles). To accomplish this you need a tool to measure shoulder bump to set your sizing die properly. After reloading and shooting thousands of rifle rounds I can attest to the fact that proper full length resizing does not reduce case life and does not adversely accuracy. If fact I've shot some of my smallest groups with full length size cases.

    The reason, for me, that full sizing is the only way to go is that I'm primarily a precision varmint / predator hunter. Functionality is just as important as accuracy for me. With full sized rounds (dedicated to a specific rifle) I never have to worry about one not chambering or extracting.


    PS: I've found that using an "O" ring under the expander button assembly thereby allowing it to float and self align aids in reducing run out. Some use an "O" ring on the locking ring of the die to aid in reducing run out. Also polishing the expander button reduced drag on the neck.
     
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  9. TrxR

    TrxR

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    A body die doesnt do anything to the neck it only sizes the body.
     
  10. jr600yd

    jr600yd Gold $$ Contributor

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    There are pro’s and con’s to using expander ball vs bushing dies. Some manufacturers supply both with their dies. Pick one method using both at the same time is not productive. Bushing dies size the neck of a fired case down to the diameter you desire. It also forces any irregularities in the neck diameter to the inside of the neck. Because of the flair in the bushing at the top and bottom you won’t be able to size the neck all the way down to the neck-shoulder junction. You’ll have maybe 1/16 of the neck not sized. Expander ball dies first size the neck down on the down stroke of the press then the expander ball is dragged thru the neck on the up stroke expanding the neck to “X” diameter. This is a major cause of case stretch. Some believe you get better concentric brass using the expander ball vs bushing.

    As for FL sizing vs neck sizing seem this keeps coming up. FL size. Only push the shoulder back 001-002. If only neck sizing after 3-5 reloads you’ll probably have to bump the shoulder back anyway.

    So, expander or bushing? Use one or the other but not both at the same time.
     
  11. 243winxb

    243winxb

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    Redding_1.JPG.jpg
    Neck sizing -The 222 had a working pressure of 50,000 PSI. Many new cartridges run at 65,000 PSI, like the old 270 win.

    Full length sizing is needed more often at high pressure. . Case volume is different between NS & FL sized. The change in case volume affects accuracy.

    Its best to have everything, exactly the same each loading. FL sizing does this.

    The bushing doesnt over work the brass neck like a standard die. [​IMG]
     
  12. Uncle Ed

    Uncle Ed

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    The problem with off the shelf factory rifles is the case neck will expand more than .004. And the factory rifle using a bushing die will have more neck runout after sizing than the Lee collet die or a full length Forster benchrest die.

    I prefer using the Forster full length benchrest dies with their high mounted floating expanders than any other type die. And "if needed" have the dies neck honed but remember when you are talking about working the neck you have no control over how much the necks expands when fired which is far more than what the expander works the neck. And you will need the expander if you do not turn the necks and the neck thickness varies more than .002.

    FL Bushing Dies vs. Honed FL Dies
    https://www.accurateshooter.com/technical-articles/reloading/fl-bushing-dies-vs-honed-fl-dies/

     
  13. SPJ

    SPJ Silver $$ Contributor

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    I’m exhausted;)
    I think so
    one good F/L bushing die that doesn’t shrink the body more than .002 is all ya need.
    Order a bushing.002 under a loaded round OD - that’s it..
    ( I like Wilson F/L your flavor may differ)
     
    Last edited: Mar 18, 2019
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  14. Enosiophobia

    Enosiophobia

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    I've been experiencing issues recently with my full length sizing dies (all Hornady). My last experiment shows the neck being pushed FORWARD by approx. .003" after full length sizing. I've always used the expander ball, perhaps because I didnt know any better, but I has read its use also aided in "truing" the neck diameter and pushing imperfections to the outside of the neck. With my 6.5 Grendel, being a gasser, many necks are slightly deformed upon ejection so this feature is key for this particular caliber / gun.

    I did a test last night and am confused why this is happening, but I suspect it's happening with all my dies as I have snug bolt closures on some reloaded rounds.

    Before:
    20190317_185636.jpg
    After:

    20190317_185738.jpg
    Any thoughts?

    Hornady once fired brass
    6.5 Grendel
    Hornady custom grade full length sizing die
     
  15. gunsandgunsmithing

    gunsandgunsmithing The best tuners and wind flags on the market Gold $$ Contributor

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    The key that is being overlooked here is die to chamber relationship. Virtually any sizing die can be adjusted for minimal shoulder bump...that's easy.
    A proper full length die will minimally size the body. Most custom dies are bushing dies, allowing us to adjust neck tension by swapping bushings. Shoulder bump and neck size are adjustable with bushing dies. What you want is a die that works with the body diameter of your fired case. That can be with a custom die that works well with your chamber or a reamer that produces a chamber and fired brass, that works well with an off the shelf bushing die, like a Redding type s full.

    The need for full length sizing has nothing to do with shoulder bump or neck bushing size.
     
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  16. gunsandgunsmithing

    gunsandgunsmithing The best tuners and wind flags on the market Gold $$ Contributor

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    Please elaborate...Before and after firing or sizing? If you're getting longer cases to the datum after sizing then you need to run the die down a bit, until it pushes the shoulder back about .002" from its fired state.
    As for the expander...ditch it or at least file and or polish it to the point that it only straightens out most of the dent from firing and ejecting. I do not want an expander touching my necks, otherwise. If the case has imperfections, turn the necks. Otherwise, the bullet will push them out, same as a mandrel.
     
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  17. DCRYDER

    DCRYDER

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    Your die needs screwed down more. If it is already touching the shellholder you may need to cut some off the top of your shellholder or bottom of your die. Right now you’re squeezing on the sides of the case and pushing the shoulder forward, you’re not touching shoulder yet.
     
  18. Enosiophobia

    Enosiophobia

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    Photos / measurement are post sizing. I'm already touching plate so I'd have to trim the die height to get more "depth". I've heard this as an option previously but find it hard to believe I need to do that. Dont think I should on a brand new set of dies. Oh well, maybe I'm learning something.
    mir_20190313_191207.jpg
     
  19. SPJ

    SPJ Silver $$ Contributor

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    Here’s a question
    With the die touching the shell holder can slide a feeler gauge under the shell holder and if so how many thousand?
     
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  20. Snuggie

    Snuggie F/TR-F/Open Gold $$ Contributor

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    I think that if folks would get rid of those expander balls in their dies and started using expander mandrels they would have less of a problem. Just my 2 cents....
     

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