1:9 twist max bullet weight 223?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by manhoer, Nov 23, 2009.

  1. manhoer

    manhoer Active Member

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    Jun 17, 2009
    I plan to start reloading soon and am curious how heavy a bullet I can fire accurately with a 1:9 twist barel in a 223 rem, and do you have any preferance in bullet type or brand with a high bc?
     
  2. montana_native

    montana_native Well-Known Member

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    Oct 4, 2008
    My AR-15 will stabilize a 75 gr A-max with 1:9 twist.
     

  3. Iowaboy

    Iowaboy Well-Known Member

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    Mar 12, 2009
    They who ever they are says around 70 is all that will stabilize in a 1 in 9 twist.

    My first savage 110 the old style pencil barreled 223 1 in 9 twist shot a 4 inch group at 600 yards shooting 80 grain nosler bthp. So just get a bunch and try them! Maybe you will be suprised.
     
  4. LouBoyd

    LouBoyd Well-Known Member

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    Oct 15, 2007
    It's not just barrel twist which determines the stability of a particular bullet Air density and velocity play a part too. Higher altitude, higher temperature, and even higher humidity all give the air lower density and help a bullet to stabilize. The higher drag of a faster bullet trying to upset it is is a little more than compensated for by the bullet spinning faster at higher velocity from a particular twist barrel.

    Bullet shape, length, and and mass distribution inside the bullet all matter. A given twist barrel can stabilize a much heavier tungsten core bullet than a copper alloy solid. For the same weight the copper alloy bullet will be much longer. For copper jacketed lead typically flat base bullets are shorter and more stable than VLD designs of the same weight.

    As others have stated the only way to know for sure is to shoot some. Keep in mind that a bullet which shoots great in hot weather or high altitude could be unstable in cold weather or lower altitude using the same rifle and loads.

    Higher humidity being less dense may seem counter intuitive, but H20 molecules are lighter than the other molecules which make up air which are N2 O2, CO2 and Ar.