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.243win. vs 6mmRem.

Discussion in 'Reloading' started by Travclem, Feb 24, 2010.

  1. Travclem

    Travclem Badass Member Lifetime Member

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    So, with my new .243 on the way (tikka t3 lite stainless), I've been going through my reloading manuals. My buddy shoots a 6mm so I've been comparing .243 loads to 6mm loads. My Lyman book says the .243 will be faster than the 6mm with the same bullets at the min and max loads. Am I on crack or does this make sence?
     
  2. RustySocket

    RustySocket

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    The 6mm has a larger case capacity... so less pressure... less velocity. Everything else being equal.

    However you can push the 6mm harder than the .243 and it is a little more tolerant of heavier bullets.

    fwiw, either will make a fine varmit rifle.
     

  3. Kahr Fan

    Kahr Fan

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    Well your on crack, the 6mm rem has a 3% larger case capacity over the 243 win if my memory serves me right, which translates to a difference of about 30-50 fps at the muzzle. At the end of the day no varmit is going to know the difference, dead is dead.
     
  4. tjpet

    tjpet

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    Strictly from a reloading standpoint I've always preferred the 6mm to the .243. More neck tension and more case capacity. Easy to run a 100grn. bullet over 3000fps in the 6mm, not so the .243.

    However, field performance on BG is the same from what I've seen the past 35 years.
     
  5. marchboom

    marchboom

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    The 6mm's longer neck can be helpful when seating the bullet closer to the rifling.
     
  6. fredj338

    fredj338

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    It's actually a tiny bit more than that, depending on brass manuf. You get 2-3% w/ the 243AI. The 243 is a true short action round. Putting a 6mm into a M700 will limit you to sim. loads as the 243, because case volumn is eaten up by deeper seating the bullet.
    http://www.chuckhawks.com/rifle_case_capacity.htm
     
    Last edited: Feb 25, 2010
  7. Travclem

    Travclem Badass Member Lifetime Member

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    I guess the lyman book pushes the .243 harder then because at the max loads, according to them, the .243 is faster.
     
  8. Travclem

    Travclem Badass Member Lifetime Member

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    The min/max carges aren't equal for the two rounds.
     
  9. RustySocket

    RustySocket

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    That was my point.

    Your looking at one set of data shot from a 24" 1:10 test barrell vs a 24"1:9 barrell

    The conditions the pressure data was generated from are not equal either. Lyman is a conservative source as well.

    Back to back, it the real world, the 6mm has more capacity and CAN be loaded to higher velocites than the .243