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Thread: Mandrel v bushing dies on case necks?

  1. #1
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    Mandrel v bushing dies on case necks?

    Has anyone tested the accuracy difference between expanding case necks with a mandrel v bushing dies? It makes more sense to me to size the area the bullet is actually touching not the opposite. Thoughts?

  2. #2
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    I assume you're talking about re-sizing fired cases? If so, you can't do that with a mandrel. Mandrels expand, bushings reduce.

    -Lee
    www.singleactions.com

  3. #3
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    Quote Originally Posted by Mram10 View Post
    Has anyone tested the accuracy difference between expanding case necks with a mandrel v bushing dies? It makes more sense to me to size the area the bullet is actually touching not the opposite. Thoughts?
    yes

  4. #4
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    I've found sizing with a mandrel produces the most consistent results with least aggro for the calibers I use, which I why I favor the Lee Collet die.

  5. #5
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    I've never gone the madrel route, so I can't speak from experience. If your necks are properly turned, what's the advantage of undersizing with a bushing then finishing with a mandrel? I get the notion of pushing wall inconsistencies to the outside edge. But if the neck is turned correctly, it should ball mic to a way less than ten-thousandth over 360 degrees. Not sure how a mandrel improves that.

    -Lee
    www.singleactions.com
    Last edited by Lee Martin; 12-13-2019 at 12:25 AM.

  6. #6
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    Quote Originally Posted by Lee Martin View Post
    I assume you're talking about re-sizing fired cases? If so, you can't do that with a mandrel. Mandrels expand, bushings reduce.

    -Lee
    www.singleactions.com
    Yes and obviously, you’d resize prior to using a mandrel to get the neck size back down to squeeze that bullet. Come on man, just answer the question

    Have YOU tested the difference?

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    Quote Originally Posted by alinwa View Post
    yes
    I expect the off the wall, non-answering posts from Al.

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    Quote Originally Posted by John Kielly View Post
    I've found sizing with a mandrel produces the most consistent results with least aggro for the calibers I use, which I why I favor the Lee Collet die.
    Thank you, Sir. Were the results slight or very noticeable to you?

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    Quote Originally Posted by Lee Martin View Post
    I've never gone the madrel route, so I can't speak from experience. If your necks are properly turned, what's the advantage of undersizing with a bushing then finishing with a mandrel? I get the notion of pushing wall inconsistencies to the outside edge. But if the neck is turned correctly, it should ball mic to a way less than ten-thousandth over 360 degrees. Not sure how a mandrel improves that.

    -Lee
    www.singleactions.com
    Advantage, perhaps in using a tool to size the area touching the bullet v sizing the outside. I haven’t tested the difference but logic seems to favor the mandrel. I could be wrong though.

  10. #10
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    Quote Originally Posted by Mram10 View Post
    Thank you, Sir. Were the results slight or very noticeable to you?
    Let me preface. I shoot F class, Target Rifle & British Match rifle so my distances are from 300-1200 yards.

    Over that range of distances, I've concluded that it's desirable to get loads with uniform low velocities & tweak them with tuners or devices performing a similar function to optimize performance generally over the full range I'm shooting. Where I can use a Lee collet, the results work for me, but where I can't do that, I use Wilson dies with no neck turn chambering, like my 6MM BR.

    For the same reason, I moly all my pills & always jump my loads.

  11. #11
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    Quote Originally Posted by Mram10 View Post
    Has anyone tested the accuracy difference between expanding case necks with a mandrel v bushing dies? It makes more sense to me to size the area the bullet is actually touching not the opposite. Thoughts?
    I've waited to see were the replies might go before my own reply.

    My simple answer is yes I have. I neck size using a bushing that produces a neck of slightly smaller ID than desired (0.001 under) then an expander die to open the neck to the desired ID size. Testing over the 4 cartridges I load for shows slightly smaller groups for those mandrel sized than those just bushing neck sized. Note that the reduction in group size is very small but for me it is worth the added effort.

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    Check out

    Could be change of neck tension more concentric

  13. #13
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    Quote Originally Posted by Mram10 View Post
    I expect the off the wall, non-answering posts from Al.
    LOL!!

    What you've not yet realized is that primarily THIS IS A BENCHREST FORUM. With guys who shoot real benchrest gear.

    Yeahh, you'll get some opinions from non-BR guys and you can do with them what you will but think about this......... why would you presume that the tiny subset of folks WHO SHOOT THE SMALLEST AGGREGATE GROUPS ON THE PLANET would all do the exact same thing "without testing"??????

    Absolutely NOBODY, not one person on this planet shooting 100/200 Group or Score uses a mandrel.

    Nobody.

    A few longrangers still use mandrels cuz they don't know no better (and can still win occasionally with a quarter-minnit gun) but they're learning.

    From being continually FLOGGED by the eighth minute guns.

    And OF COURSE we've "tested"..... every friggin' day shooting is a "test"...... and if somebody started winning while dragging their casenecks back over a sizing mandrel then ever'body would test it all over again..... but WINNING is the real "test."

    Yet you "assume" ever'body's just a bunch of lemmings? That you are "better?" Cuz your common sense tells you "mandrel=better"......????

    Show some rows of 1/10 inch groups..... post some pix of rows of 5-shot dots that you fired from your "awesomely consistric reloads"


    I can go shoot a row of dots right now.... I can go out and turn the lights on on the range and shoot 25 shots in a row without sighters and there won't be any paper in the 5 round groups..... and send an auto-dated camera pic....on call, any time......day or nite


    And you don't even fire sighters, nor know why you would.....



    Mayhaps if you asked QUESTIONS like "hey, how come you'se guys use sizing buttons instead of mandrels?" instead of cluttering the thread up with your totally unsupported assumptions and guesses you'd get more useful interplay....

  14. #14
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    and the guy who you answered you who actually shoots BR you get all snotty with..... maybe you should know who Lee Martin IS before you get all uppity wit' him!


    silly wabbit

  15. #15
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    funny thing is.... I probably know the only rifle reloader on God's Earth who's actually never dragged a mandrel thru a neck. Cuz he's only loaded for one gun, his Borden-Built 6PPC with Borden-Built Brasses and Dies...... so I guess heem, since't he's never even SEEN a sizing mandrel I can honestly say should have no opinion.

    Most others have done both....... and have chosen one ....... from "experience"


    (It's a lot like "testing"....... only better)

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