Barrel twist

Discussion in 'Long Range Hunting & Shooting' started by jpbaker, Feb 26, 2011.

  1. jpbaker

    jpbaker Well-Known Member

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    Hey, im a bit confused, and plz excuse my ignorance.

    Im in the process of ordering some "stuff" to put a rifle together.

    this is what I have:

    - stevens/savage action
    - Bell and Carlson A2
    - Nikon Buckmaster 6-18x40SF BDC

    This is what im trying to order:

    Krieger 7mm #5 SS Barrel.

    What im unsure about is what to order for a twist.
    my options are 1:8-10 in .5 incriments.

    OK, now I understand how the twist works, and what it does, but how do I determine what I need?

    TKS
    Jordan
     
  2. jrw1976

    jrw1976 Well-Known Member

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    To determiner your twist you will first have to decide which size, type, and weight of the bullets you want to shoot.
     

  3. 805_Sniper

    805_Sniper Well-Known Member

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    Krieger or Hart barrels are a great choice. You will be pleased with either. Twist rate depends on what bullet you plan on shooting out of it. Typically the heavier the bullet, the bigger the twist is required to help stabilize them. Length plays a role too. I have a krieger on my 7mm with a 1-10 twist, 26" long. Im shooting 180gn. Berger VLD's. It shoots 0.25 M.O.A @ 100yds. I hope this helps!
     
  4. jpbaker

    jpbaker Well-Known Member

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    removed
     
    Last edited: Feb 28, 2011
  5. jpbaker

    jpbaker Well-Known Member

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    OK since the stevens/savage action does not come chambered in the 7mm WSM like I want, how much work is involved to convert it.

    TKS
     
  6. jrw1976

    jrw1976 Well-Known Member

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    The bolt head will need to be changed and if it was me I would build it on a long action.
     
  7. Nape.270

    Nape.270 Well-Known Member

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    Get a long action in a magnum caliber and all you will have to do is screw on your new barrel.

    As for barrel twist it depends on the bullet you want to shoot but also how fast your going to shoot it.

    7mmWSM you will probably need a 1 in 8.5 to shoot 180gr vld's
     
  8. elkaholic

    elkaholic Well-Known Member

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    I am quite surprised that you are able to shoot 1/4 moa with a 10 twist when shooting 180 vld's! A 1:8 or 8 1/2 would normally be required for that bullet......Rich
     
  9. rscott5028

    rscott5028 Well-Known Member

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    I've heard of exceptions where a gun with a slower than recommended twist will shoot fine with the longer bullets. But, that is certainly the exception. Invariably, it has always caused me grief and I've never been able to overcome slow twist with increased velocity to achieve best accuracy. Going from a 1:9" to a 1:10" twist has a much larger influence on the RPM than an extra 200-300 fps velocity.

    Choose your preferred bullet and get the proper twist, if you are interested in long range, you will want to err on the faster side. The barrel maker should be able to assist you.

    Also, the bullet maker will often have a recommendation as well.

    Berger recommends a 1:9 twist to stabilize the 180g VLD properly.

    Unless you are shooting benchrest competition where they need everything to be perfect for exactly one bullet, then it is better in my opinion to err towards a little too fast than too slow when using modern bullets in a hunting rifle.
     
  10. azsugarbear

    azsugarbear Well-Known Member

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    Lilja barrel's website has a chart you can use. Just match up the caliber with the weight of bullet you intend to use and the table will give you the recommended twist. here is the link:

    Lilja Precision Rifle Barrels - Caliber and Twist Rates

    Just keep in mind that these are general recomendations. Speed can compensate somewhat for a slower twist. For example, a .308 Win with a 1-in-11 twist would probably not be able to stabilize a 200 gr. bullet. But a 300 RUM with the same twist would be able to stabilize that same bullet because it is pushing it about 400-500 fps faster.
     
  11. jpbaker

    jpbaker Well-Known Member

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    Great TKS!!!
     
  12. rscott5028

    rscott5028 Well-Known Member

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    Weight is the most commonly referenced factor. But, bullet length is equally or perhaps even more important regarding stabilization. So, all copper bullets such as Barnes and Swift Scirrocco will be longer than jacketed lead bullets of the same caliber+weight and will require a faster twist, usually about the equivalent to the next heavier weight bullet in that caliber.