Necking down from 6.5 to 6mm

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Iron Worker, Mar 9, 2011.

  1. Iron Worker

    Iron Worker Well-Known Member

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    Just got off the phone from Redding . Mentioned I've been sizing 6.5x284 to 6 x284 in one shot by running the case in their Type C series FL sizeing die. They said "I should be sizing it first in their standard seating die and then next step in the FL die I have". So now I'm wondering if I have the Do-nut effect inside the necks of my brass ? Can I see that from just looking in? Our do I need to run a paper clip are some thing to feel for it ? Hope I haven't ruined some expensive Lapua brass ?
     
  2. SBruce

    SBruce Well-Known Member

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    The "donut" is a wierd thing. I am a little confused by that theory myself, so it would be nice to hear some other opinions.

    I heard that the donut is created when necking up brass, which would make more sense (to me anyway). Makes sense that the neck shoulder junction wouldn't want to expand fully or as easily as the neck itself does, and therefore would be a smaller ID once the neck up has been done.

    I am failing to visualize how necking down would create a smaller ID at the shoulder junction (based on the same logic of that portion not wanting to move as easily).

    FWIW, I just neck size partially with a neck die (not the full length of the neck) and seat bullets and fire. They chamber just a little snug, because there is now a "false shoulder" where the neck die stopped sizing down, but it's only snug for that first fireing (unless it's a really warm load).

    I'd like to hear other opinions myself.
     

  3. Edd

    Edd Well-Known Member

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    I neck 280 Remington cases down to 6mm in one step with a full length sizing die. I've never had any issues.
     
  4. gr8whyt

    gr8whyt Well-Known Member

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    I'm confused. How do you size a case in a seating die? A seating die does not alter case dimensions in any way. I'm also curious because I plan on doing similar from .277 to .257.

    -- gr8whyt
     
    Last edited: Mar 9, 2011
  5. Iron Worker

    Iron Worker Well-Known Member

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    Ok fair question. Were sizing 6.5x284 down to 6x284. 1st step is a 6x284 seating die not a 6.5. So its does partially size the 6.5 down to 6mm then the final step is in the 6x284 FL sizing die. The tech at redding said " I'll have a more uniform neck ,if done that way"
     
  6. MontanaRifleman

    MontanaRifleman Well-Known Member

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    I can't say whether or not you have a donut inside, but if you do, you should be able to take care of it with a neck turning reamer.
     
  7. CPGfan

    CPGfan Well-Known Member

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    I have sized probably 1000+ cases just the way you described, you are fine doing it just the way you are.
     
  8. Iron Worker

    Iron Worker Well-Known Member

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    Do you mean not the way the Redding tech suggested ?
     
  9. CPGfan

    CPGfan Well-Known Member

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    Yes. I just take 6.5x284 Lapua brass and run them through my 6mmx284 sizing die. I lube the inside of the necks good as well as the outside, pull the ram, prime, dump some powder in, seat a bullet, and go to boomin!! It works just fine that way
     
  10. AZShooter

    AZShooter Well-Known Member

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    I just put together a 6mm-284. I chose 6.5-284 norma brass and used a hornady die set. The FL die worked but the die's neck ID was .264" which IMO is too small. The die sized the necks way past a useful dimension and pulling the necks over the sizer ball was extremely difficult even with imperial sizing wax inside the necks. The end result was some very stiff necks and high neck tension. The necks were so stiff that seating or pulling a bullet was unbelieveably hard. I had to ruin bullets in a RCBS collet die to remove them from loaded rounds. I wasn't sure if the brass was work hardened or improperly anealed from the factory.


    After this mess, I talked to Redding and they also said to use the seating die as the first step. I asked if I could perhaps use a series of bushings in a S die and they said it wouldn't work.

    I ordered 100 pcs of Lapua brass and made my own forming die. I chopped off the shank section of a burned out .264 win mag, threaded it 7/8-14 and ran in the reamer. The result was a die that necked the brass from .290" to .277". Then I used a .272 bushing in my S series die. No overworking of the necks and no running over a sizer ball.


    FYI the redding FL die will reduce the OD of the necks to .268".

    You can buy a die blank from several sources and get your gunsmith to chamber it, shouldn't cost much and IMO it would be money well spent. Redding seating die costs $56. Your choice.