primers for low extreme spread in 264

Discussion in 'Reloading' started by bullfrog, May 7, 2012.

  1. bullfrog

    bullfrog Well-Known Member

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    Jul 27, 2010
    What primers has everyone found to give the lowest extreme spreads with Retumbo powder in the .264 win mag? I'm using CCI 250 and F215M with extreme spreads running 40-60 fps. I would like to lower this.

    I have already tried with and without dry neck lube.
     
  2. rscott5028

    rscott5028 Well-Known Member

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    Apr 18, 2010
    I don't shoot that cartridge or powder. But, Fed gm215m is a good and consistent primer.

    Assuming you've already zeroed in on an accurate load to begin with.

    Most often, I find that high ES/SD is related to inconsistent brass prep. ...specifically neck wall thickness variation (turn and/or use bushing/collet die)

    Also, chrony readings can be fooled with lots of muzzle blast. Move the chrony out farther if possible. Verify actual groups at long range.

    -- richard
     

  3. Gunpoor

    Gunpoor Well-Known Member

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    I used WLRM Winchester primers in the two 264Win I loaded for and had no problems with ES, but didn't use Retumbo. What I have found with the really slow powders is they require top end pressure to get the load to stabilize and therefore tighten the velocity spread.
     
  4. lloydsmale

    lloydsmale Well-Known Member

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    Feb 5, 2012
    another vote for fed match mags. I have better luck with them in mags then any other primer.