Type S Bushing Dies

Discussion in 'Reloading' started by J E Custom, Jul 11, 2009.

  1. J E Custom

    J E Custom Well-Known Member

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    I would like every ones opinion of these dies and the way/method of choosing the
    right bushing. I know how Redding recommends to size the bushings but would prefer
    hearing from the members and taking advantage of all of the experience with them.

    Thanks

    J E CUSTOM
     
  2. woods

    woods Well-Known Member

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    For me, the first consideration is the neck thickness of the brass or what thickness you are going to turn the necks to. The bushing dies size the outside of the neck to a certain dimension. In doing so, they will push all the variations in neck thickness to the inside of the neck. So that is why I only use the bushing dies on necks that I have turned to a consistant thickness.

    It will also depend on whether you have a tight necked chamber. For instance on a 338 RUM I have a fired case OD neck measurement of .366". Since I want .003" clearance that would mean I want a loaded OD neck measurement of .363". The bushing size will then depend upon how much bullet grip I want, say .002", then the bushing size will be .361".

    Then I calculate what thickness to turn to by subtracting the caliber from the desired loaded OD neck and dividing by 2

    .363"-.338"=.025/2=.0125"

    and turn the necks to that .0125".

    On a factory chamber where there is a lot of neck clearance then I will measure all the brass neck variance and turn to the lowest common measurement. If the brass varied from .013" to .015" then I would turn to .013". So then the bushing would be chosen by adding the caliber and 2 times the neck thickness and subtracting the bullet grip

    .338"+.013+.013= .364"-.002"=.362"
     

  3. AJ Peacock

    AJ Peacock Well-Known Member

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    Woods, don't you take into account springback? Your last equation is what I use, except I subtract .001" to account for springback in the brass.

    AJ
     
  4. woods

    woods Well-Known Member

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    Yes, I do take into account springback but that would have complicated the explanation a lot more. Springback changes with the number of firings on the case or if you have annealed. The way I deal with that is to order a bushing on either side of the target. Then size a case and use pin gauges
    [​IMG]
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    to determine actual inside neck dimensions and use the appropriate bushing.
     
  5. MontanaRifleman

    MontanaRifleman Well-Known Member

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    JE,

    I just opened this forum to start another thred on bushing dies and saw yours. I am just going through this process - first time bushing die sizing... for a 300 RUM.

    I wanted to order the dies and bushing, but had ne way of no how large a bushing I needed (and you really need to turn the necks for this process as already explained). Sooo.... I took a couple of pieces of brass and neck sized them with my 300 WSM die so I could turn them. I turned them then measured the OD. Then I seated a couple of bullets in them and measured the OD again (this is the important measurement) I subtracted .001 (for .001 tension) and came up with .333 for a bushing diameter, which BTW, is the same OD I get if using the expander ball.

    I loaded up 50 rounds yesterday for 5 different powder/bullet combinations for max load testing. With 180 gr E-Tips seated at 3.690 I ran into compressed loads with 99-102.5 grs of Retumbo. The .001 tension was not enough to hold the bullets down with the higher compressiojn. I had to re-cam the lever several times to get the bullet to seat.

    I'll be asking some other related questions in my thread.

    -MR
     
  6. J E Custom

    J E Custom Well-Known Member

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    Thanks for the info everyone.

    I turn all of my necks during prep of new brass.

    But the ,001 neck tension did not sound right so I wanted to see what everyone else was doing
    and I normally use .002 radius (.004 dia ) and I didn't want to have to do it twice.

    Again Thanks !!!!

    J E CUSTOM