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Thread: which bushings?

  1. #1

    which bushings?

    So im looking at getting a better set of dies for the 7-08, ones which have bushing dies. When ordering the bushings, are these relative to the outside of the neck and if so, does it allow for any spring back? for example, my case walls are 0.015 thick, the bullet is 0.284. thus the overall loaded outside diameter is 0.314. Ive been told that ideally you want a minimum of 3 thou neck tension and probably max 5 thou. So, if i want say 4 thou, do i just order a 0.310 neck bushing? Or am i likely to find that this actually squeezes the case to 0.310 outside diameter and when released from the die, springs back to say 0.312? This is obviously important to me as i could end up getting a bushing which in theory is right but in reality leaves me with too little neck tension?

  2. #2
    Im looking at this also. Im waiting on my variation for 7-08 and want to get decent dies from the get go and replace my .243 also.

    Redding are now recommending a tension of 1 thou.
    I'd rather have a bottle in front of me than a frontal lobotomy!
    Another 7mm08 shooter!

  3. #3

    Although it's not cheap, I suggest you get a range of bushings. Your calculations look spot on and I am nominally applying 3 thou of tension, but my necks vary a bit. I had been using a .269 bushing for the final pass on my .243 brass, but found some necks were loose, so I just ran the brass through again with the next bushing down.

    The following article is worth a read:

    Regards JCS
    Last edited by jcampbellsmith; 05-06-2011 at 16:36. Reason: url added

  4. #4
    My loaded brass comes in at .271 which seems rather skinny seeing as the fired brass is .277
    I'd rather have a bottle in front of me than a frontal lobotomy!
    Another 7mm08 shooter!

  5. #5
    i measure outside of loaded round -2 to -3 thou thats the bushing you need

  6. #6
    Distinguished Member Ronin's Avatar
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    Oct 2014
    Lancs / Cumbria Border
    First of all, you are correct in the way you calculate bushing sizes.

    If the overall neck diameter (case wall thickness x2 + bullet diameter) = .314", then for .002" neck tension, you want a .312" bushing.

    All well and good so far.


    if your rifle is a standard chamber, and you have not turned your case necks to a 3/4 clean up of the neck to uniform the wall thickness you are wasting your money on bushing dies.

    In a standard chamber you may get some benefit from using bushing dies if you clean the neck.

    You only really see benefits of using bushing dies with tight neck (fitted neck) chambers which are predominatly custom rifle / rebarrelled rifle territory.

  7. #7
    thanks for the info.. some useful stuff there. Reasons ive been looking at the neck tension is because it should increase case life and also i have noticed with conventionally sized cases (using an expander) that when seating the bullets, some require more pressure than others.. I was hoping that using neck bushings without an expander ball may reduce this. Ive had my cases checked, they came back at around 1 thou runout, i thought with those results, it would be fine to go ahead with neck tensioning?


  8. #8
    Distinguished Member Ronin's Avatar
    Join Date
    Oct 2014
    Lancs / Cumbria Border
    .001" runout from brass that hasnt been prepped in any way and from (I am guessing) a standard chamber is good.

    Personally, I do not thing expander balls are necessary - I grind down or remove them in my own dies.

    If a case neck gets damaged - I have a tool to bring them back to uniform size.

    Be interested to hear what accuracy you are getting at the moment, before you change anything.

  9. #9
    redmist.. with the load at the moment im getting 0.75MOA average. The ES is more of the issue which is between 30 and 50fps. Ive been having pretty good results of vertical spread at extended ranges of less than 0.6 MOA at 500yds.

  10. #10
    Quote Originally Posted by bk View Post
    ...Redding are now recommending a tension of 1 thou.
    A recommendation I followed and am now having to return the bush for one 3th less than the OD of a loaded round. 1th neck tension and the bullet just dropped inside the brass .

    Ignore Redding and get -0.003"

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