Lee collet die

Discussion in 'Reloading' started by buck52, Jul 14, 2010.

  1. buck52

    buck52 Member

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    Hi
    Decided to get some reloading done for my .308.
    I have serviced my collet die, polished lubed etc but when I return the press handle to the top I have to push like hell to get the mandrel to come out of the case, I have the die adjusted so that I have just enough neck tension without undue pressure, any suggestions please.

    PS. Just measured the case after sizing, the inside measures .300, thats sizing a bit tight for a .308 cal is'nt it?
     
    Last edited: Jul 14, 2010
  2. justgoto

    justgoto Well-Known Member

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    I've read somewhere that the elasticity of the case is about .002. If you were to size it down to say .304 then set a bullet measuring .308, pulled the bullet the case would then measure .306 due to elasticity.

    So, I would think that you would only need to size it to just under .306 at the most to obtain sufficient tension. Both my 30-06 and 30-30 mandrel are .306.
     

  3. buck52

    buck52 Member

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    Thanks, I thought it was a bit tight, how do I regulate/set up the tension?
    My ammo is only used for hunting in a bolt action.
     
  4. justgoto

    justgoto Well-Known Member

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    It seems to me that your mandrel is too small. You should not be able to get the case mouth to that small of diameter. It just seems that something other than adjustments are to blame.

    You didn't happen to disassemble other dies also, then get parts mismatched?
     
  5. buck52

    buck52 Member

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    No, only got one collet die, i did polish the mandrill with 1500 grit.
    I though the max tension was determined partly by the fingers of the collet coming together.
     
  6. Aldon

    Aldon Well-Known Member

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    No matter how tight the diameter it should not be that difficult to remove the mandrel.

    It sounds like you may be fighting a vacuum.

    Are you sizing the necks post primer?

    I had similar situation although not as exacerbated and now prime my brass after initial neck sizing with collet die.

    The collet die uses both the collets and the mandrell to size the necks.
     
  7. Jinx-)

    Jinx-) Well-Known Member

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  8. boomtube

    boomtube Well-Known Member

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    "I've read somewhere that the elasticity of the case is about .002. "

    It's more like half that, or even a tad less. Check it yourself, mike the neck of a loaded round, pull the bullet and mike it again, at exactly the same place. It won't be more than one thou difference.


    Buck, the mandrel of your Lee Collet Neck Die is the neck diameter control, not the collet. All the collet fingers do is squeeze the neck into mandrel contact.

    You have "polished" the mandrel down too small at the squeze point so the remaining original diameter lower portion of the mandrel is acting as a conventional expander. That's NOT a big issue but it will help if you lube inside the necks now. Actually, it will also help if you back the die out a bit and/or reduce the lever pressure so the necks are sized a bit less than the absolute maximum.
     
  9. woods

    woods Well-Known Member

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    This is the Lee Collet
    [​IMG]

    and with it disassembled showing the mandrel and the cap
    [​IMG]

    use your calipers and mic the mandrel. It should be .306". If it is not then you have a bad mandrel and Lee will send you another one.

    If you are camming the press over, IOW if the lever stroke goes all the way down, then you are not using the Lee Collet correctly. If you are camming the press over then all you are doing is putting more pressure on the die and your press than is necessary.