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Barrel twists on your fav .338 long range gun

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Black Diamond 408, Nov 18, 2003.

  1. Nov 18, 2003 #1
    Black Diamond 408

    Black Diamond 408 Well-Known Member

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    Im currently working on a project by necking the 505 down to .338 cal. I'm wondering what twists your longrange guns have, bbl length and the speeds you run with the Sierra 300gr bullets. I want to compute the twist i will need for this bullet, the new case should be capable of launching the bullet at speeds over 3500fps. I need to have a twist that will not over spin the bullet so it will stabilize out at 1000yds or farther. I have a pic of the formed case if any one wants to see it i can email it to you. It most likely will have a 35deg shoulder.

    DC did a workup on the wildcat and it looks very promising!! [​IMG]
     
  2. Nov 18, 2003 #2
    Darryl Cassel

    Darryl Cassel Well-Known Member

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    My two 338/416 IMP has a 10 twist.

    The 37" barrel on the one has produced 3310 FPS using the 300 Gr Sierra MK.

    The case has a 35 degree shoulder.

    Later
    DC
     
  3. Nov 18, 2003 #3
    Thunder Hunter

    Thunder Hunter Active Member

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    Black Diamond try this email address that a friend just gave me on the same subject. Loadammo.com
     
  4. Nov 18, 2003 #4
    chris matthews

    chris matthews Well-Known Member

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    I don't feel you can "over spin" a bullet as I have shot several fast twist guns with light bullets and had no problem. However I tend to go with the slowest twist I can get away with. For example- 1 in 11 for 300 Win Mags up to 210 gr bullets. Boots Obermeyer uses a 13 for 190.
    You can literally spin the jacket off in too fast on light made bullets.
    To answer your question a 10 will work great or maybe a little slower. Remember, the faster you push the bullet, you can get away with a slower twist.
     
  5. Nov 18, 2003 #5
    Black Diamond 408

    Black Diamond 408 Well-Known Member

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    Thanks Thunder, ill check it out.

    Thanks Chris! I want to get it right the first time,,$$$$$
     
  6. Nov 18, 2003 #6
    kidcoltoutlaw

    kidcoltoutlaw Well-Known Member

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    338/416 IMP what head size is it.is it the same as the 338 RUM,thanks,keith
     
  7. Nov 18, 2003 #7
    Perkules

    Perkules Well-Known Member

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    According to almost everyone here,the twist for .338 300 MK:s is 10". Man,I was more than happy to find out that my TRG-S has a 10" twist (instead of the still advertised 12"), otherwise I´d stayed with 250 grainers.

    Very low ES,some bedding things to fix now but my first shot is always where it´s supposed to be with the MK:s and the deer are out there now...

    The Greenhill Formula gives you 9.95" for that combo too.