Barrel twist question?? 7WSM / 180 Bergers

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Ryan55555, Nov 2, 2010.

  1. Ryan55555

    Ryan55555 Well-Known Member

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    I am currently building on a Savage action a hunting rifle in 7WSM with plans to shoot the Berger 180g bullets. Barrel length will be 26in.

    I ready to order a barrel but want to make sure I know what I want.

    What twist would be recommended? I was thinking 1:9, but have also thought about 1:8.5

    Any suggetstions or comments would be appreciated.

    Thanks,

    Ryan
     
  2. BryanLitz

    BryanLitz <b>Official LRH Sponsor</b>

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    Ryan,

    Both will work fine. Just don't go slower than 1:9" if you want to shoot the 180's. I know of someone who went real fast (1:7" or 1:7.5") and had problems, but 1:8.5" isn't too fast.

    Good shooting,
    -Bryan
     

  3. TORCHRIDER

    TORCHRIDER Well-Known Member

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    Don't want to hijack, but I am also interested in building a 7mm WSM on my Savage long action shooting the 180 Bergers. How long a throat should I be asking for in a new barrel?
     
  4. Derek M.

    Derek M. Well-Known Member

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    1-9 is perfect. I have a Shilen 7mm 1-9 on order and the caliber is either going to be 7WSM or 280.
     
  5. Ryan55555

    Ryan55555 Well-Known Member

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    Good question Torchrider

    I have no idea on throat dimension. Hopefully someone with experience will chime in.

    My build will also be on a long action savage.

    What barrel are you planning on using?

    I am leaning towards a Brux barrel chamber by SinArms.

    This is my first custom barrel so I have no prior experience.
     
  6. BryanLitz

    BryanLitz <b>Official LRH Sponsor</b>

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    You can find dimensions on all Berger Bullets for planning chambers/throats at this address:
    http://bergerbullets.com/Quick Reference Sheets 9-23-10.pdf

    Also, for the 168 and 180 VLD's, there are prints here:
    http://www.appliedballisticsllc.com/index_files/7mmNumberOne.pdf

    I would aim to have the bearing surface just ahead of the neck/shoulder junction when the bullet is seated ~.060" off the lands. This gives you the flexibility of going into or off the riflings while having enough of the bullet in the neck, and not seating it past the 'donut' (ring of thick brass that forms at the base of the neck after several resizings).

    -Bryan
     
  7. Ryan55555

    Ryan55555 Well-Known Member

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    Thanks Bryan - Lots of good information here.

    Some of it is over my head but I am learning a ton.