Using a Mandrel to open-up, expand neck on cartridge.

Discussion in 'Handloading and Reloading' started by marine one, Feb 14, 2021.

  1. marine one

    marine one Member

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    hello everyone,
    I've ben away for awhile, but I'm back, came across a mandrel die from 21st Century, Just checking
    has anyone used one of these? Did they find it usfull, what about concentrisity?
     
  2. Walkalong

    Walkalong Moderator Staff Member

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    They work great, the mandrel floats in the expander body, so if your case is straight, it still will be after expanding. Can't go wrong with the Sinclair or the 21st Century, mandrels will work in either.
    Sinclair & 21st Century Expanders @ 35%.JPG Sinclair Gen II Expander Die Body and TIN Coated .241 Turning Mandrel Pic 2.JPG
     
  3. Walkalong

    Walkalong Moderator Staff Member

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    The 21st Century hand primer is the bomb.
    21st Century Priming Tool Pic 1 @ 40%.JPG
     
  4. GoldieMI
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    GoldieMI Contributing Member

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    +1 for the Mandrel setup
    I have the Sinclair Body and 21st Century Mandrels.
    Work great for me
     
  5. Obturation
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    Obturation Contributing Member

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    Thanks @Walkalong , like I need more things to NEED.
    That is a beauty.
     
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  6. Howland

    Howland Member

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    I'll be another voice in favor of mandrels. I have a 21st Century set and feel it was money well spent.

    I got them for 338LM. My most accurate charge weight was on the low end of the powder charge scale but ES was horrible and I doubt accuracy would hold up at distance. I thought tighter grip would help the slow powder get more consistent ignition. I proved that theory wrong but did conclude that 0.003" interference fit gave the best accuracy. I would never have found that out without testing.
     
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  7. marine one

    marine one Member

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    SO it seams that everyone is in favor of using a mandrel, I have a question, about using the expander body with mandrel, most cases after there fired
    expand so if I'm reloading the same case don't I resize the neck down to hold bullet ???
     
  8. Walkalong

    Walkalong Moderator Staff Member

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    I use a full length bushing sizer with no expander ball, then expand with the mandrel, but yes, you have to size at least the neck, and I advise to full length size
     
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  9. GoldieMI
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    GoldieMI Contributing Member

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    +1 here...
     
  10. marine one

    marine one Member

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    Walkalong, If I use a redding full length resizer
     
  11. marine one

    marine one Member

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    Yes, I used a RCBS F/L DIE today with out the expander ball and it reduced the neck size by couple thousand, so know I can use the mandrel to
    open up neck. This means that I'm opening neck twice, when using a Redding bushing neck die I only size neck once.
    What say you.
     
  12. griff383

    griff383 Member

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    You can take the expander out of the FL die and set up a 2 step process. I do it this way and use the 21st century mandrels. I love them and do all my bottle neck cartridges the same.

    First I check that the FL die is set up to either bump the shoulder 0.002 or do a full sizing for autos pending the use. Then use a mandrel to expand necks. Yes it's an additional pull for each case but the consistency is perfect. Plus, you can really dial things by being able to select exactly how much expanding you want or need vs what the die manufacturer sends you
     
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  13. jmorris

    jmorris Member

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    Bomb, there’s a word I don’t like to use in conjunction with hand. :)
     
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  14. Walkalong

    Walkalong Moderator Staff Member

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    No, you removed the expander ball from the die, so it only sized down the neck, then you expand it once with the mandrel, the same as if you had left the expander ball in the die and used only the die.
     
  15. marine one

    marine one Member

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    Thank you all for responding, It's grate to back with you guys! , I wasn't sure how to use this die in conjunction with F/L die.

    Thanks Again.
    Dennis
     
  16. Kaldor

    Kaldor Member

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    I stopped using expander balls a long time ago and went to all mandrels.
    You can also use a Lyman M-die as a mandrel. I use one in my progressive with a bullet feeder to make my life easier.
    I also own a Sinclair with TiN coating for use in my Mec SS.
    The 21st Century ones you can get alot of different diameters, so they might be a bit better if you want something other than 2 thou.
     
  17. AJC1

    AJC1 Member

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    Before mandrels were easy to get guage pins were tapered and used... if your using a lot of different calibers it may still be a good option. The collet die can be used to hold them if you have the collet for that caliber
     
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