neck terning

Discussion in 'Reloading' started by col48, May 3, 2006.

  1. col48

    col48 Well-Known Member

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    Hi all

    I am trying to decide whether to neck tern my 270 brass or not.
    I have a 270 wsm lilja bbl minimum sammi speck chamber.
    I have Norma brass.
    Now i am thinking of getting my bushes for the redding comp die,it is a full custom rifle.Do i need to neck tern with that speck chamber,or would you leave the brass,
    Or i could take of 80% and uniform them.
    The reason i am asking is when i neck terned my last 270 wsm cases for a factory rifle,And then shot some that had not been done,the non neck terned ones shot the best.(But this was a factory stick)
    So what do you lot think.

    And how much neck tension would you start with for a rifle with a mag.

    Thanks for the help
    Colin
     
  2. Ballistic64

    Ballistic64 Well-Known Member

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    If it were me, with Norma brass and a minimum spec chamber,I dont think I'd bother.Do you know the actual neck dia. of the chamber?
     

  3. col48

    col48 Well-Known Member

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    [ QUOTE ]
    If it were me, with Norma brass and a minimum spec chamber,I dont think I'd bother.Do you know the actual neck dia. of the chamber?

    [/ QUOTE ]

    no but may be nesika will,they built the rifle
     
  4. Bart B

    Bart B Well-Known Member

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    If your case necks don't vary in thickness by more than .001 inch, neck turning usually isn't needed. Either way, your cases will center at the front of the chamber when the firing pin drives them hard into the chamber shoulder. As long as your sizing die leaves a case with a straight neck, that's fine.

    I'd use a bushing .002 or .003 inch smaller than a loaded round neck diameter. Depending on how much spring back the necks to, the bushing .003 inch smaller one may be best.
     
  5. col48

    col48 Well-Known Member

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    [ QUOTE ]
    If your case necks don't vary in thickness by more than .001 inch, neck turning usually isn't needed. Either way, your cases will center at the front of the chamber when the firing pin drives them hard into the chamber shoulder. As long as your sizing die leaves a case with a straight neck, that's fine.

    I'd use a bushing .002 or .003 inch smaller than a loaded round neck diameter. Depending on how much spring back the necks to, the bushing .003 inch smaller one may be best.

    [/ QUOTE ]

    thanks bart
     
  6. col48

    col48 Well-Known Member

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    [ QUOTE ]
    If it were me, with Norma brass and a minimum spec chamber,I dont think I'd bother.Do you know the actual neck dia. of the chamber? [/quot
    dose this mean anything to you.


    TPI in 20 Inches
    Body TPI 0.115
    Neck TPI 0.034
    Throat TPI 0.5237
    Pilot Size 0.27
    Caliber 270
    Bore Size 0.027
    Groove Size 0.277
    Basic Brass 270 WSM
    Resize N.D. 0.296
    Margin .001/.003
    Tolerances MAT'L.
    Unless Otherwise Specified PACIFIC TOOL DWG. BY Dave Kiff
    Fractional ± .001 598 Avenue C Checked MK
    Decimal + 0.0004 White City, OR 97503 Approved
    Angular ± 1/4 (541)826-5808 Sheet

    thanks
    colin
     
  7. Ballistic64

    Ballistic64 Well-Known Member

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    col48, take a measurement of one of your loaded rounds just for curiousity.I talked to Dave,and while he didnt have the exact neck dia. spec Nesika uses,he was guessing .312-.315
    Nesika usually makes thier guns to a match chamber but unless the customer specifies a tight neck,they have to chamber looser for what ever the customer shoots.To improve accuracy on thier guns Neskia will use a min. saami chamber spec with a tight throat.My guess that without turning your neck clearance is already .004-.005 and being as Norma is pretty uniform brass,thats why I said I wouldnt mess with it.Just for curiousity sake can you post the loaded neck dia.?
     
  8. col48

    col48 Well-Known Member

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    [ QUOTE ]
    col48, take a measurement of one of your loaded rounds just for curiousity.I talked to Dave,and while he didnt have the exact neck dia. spec Nesika uses,he was guessing .312-.315
    Nesika usually makes thier guns to a match chamber but unless the customer specifies a tight neck,they have to chamber looser for what ever the customer shoots.To improve accuracy on thier guns Neskia will use a min. saami chamber spec with a tight throat.My guess that without turning your neck clearance is already .004-.005 and being as Norma is pretty uniform brass,thats why I said I wouldnt mess with it.Just for curiousity sake can you post the loaded neck dia.?

    [/ QUOTE ]

    hi
    i have the chamber drawing,but am unable to put it on hear.
    a loaded round is .3085
    if you send me a email i will send you the chamber drawing.

    col48@ukonline.co.uk

    it is minimum saami speck
    thanks
    Colin
     
  9. Ballistic64

    Ballistic64 Well-Known Member

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    Colin, I couldnt figure out how to post the reamer drawing either and probably shouldnt without Daves permission but it is a .315 neck dia. So youve got a total of .0065 neck clearance (.00325 per side).Norma brass is pretty uniform and IMO you have little to gain by turning.I havent seen the Norma WSM brass,but WSM brass is fairly thick (by your measurement must be close to .016")so if you are finding a little variance in the brass,its not going to hurt to clean it up.Youll probably find bigger accuracy gains in your other components.
    When you get a chance to shoot post up some pics.Ive always had some interest in the short mags.Im getting closer to having a 300 saum worked over by Kirby.Cant wait to try it on some prarie dogs. /ubbthreads/images/graemlins/grin.gif
     
  10. col48

    col48 Well-Known Member

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    hi Ballistic64
    i am waiting for my McMillan stock to come,they are running behind.my m8 has the 300 wsm so i will see if he will put some picks of that up as well.(he is waiting on a stock as well)when i get round to micing my brass i will see how uniformed it is,if its say within .001 i will leave it alone,
    if more than that should i take of about 80% ????

    how much neck tension would you start with.???
    it has a h&s box mag.
    the last 270 wsm i had was a cracker (tikka t3 ) they seem to be shooting very well,in fact my m8 used to shoot the 30 06 but is giving the 300 wsm a go after seeing how well the 270 wsm of mine shot.that shot 1/2 moa @ 100y all day.but that was with out cleaning up the necks,(win brass)but when i took of 80% it shot crap.(factory chamber,)

    thanks again for your help
    Colin
     
  11. Ballistic64

    Ballistic64 Well-Known Member

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    I doubt if you'll find your brass out more than .001,but if it is, and it was mine, I'd clean it up.I'd agree with Bart and go .003 under your loaded round for the neck sizing.Sometimes a light tension can improve accuracy but its not a good idea with a magnum and loaded rounds in the magazine.