Twist rate for 308?

Discussion in 'GSSF' started by armorplated, Feb 9, 2010.

  1. armorplated

    armorplated

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    I'm shopping for a bolt action rifle for medium to medium heavy game. I was looking at the 243 but think I like the 308 better.

    1 in 10 twist would handle the heavier bullets best and would allow me to load the cartridges to the rifling.

    But the rifle I'm considering is the Left Handed Tikka stainless lite, and it's only offered in a 1 in 11 twist.

    Significance?
     
  2. TrooperBrian

    TrooperBrian

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    It just so happens I learned about twist while barrel shopping yesterday. A 10, 11, 12 barrel is best for bullets in the 150-168 grain. Hope this helps you narrow things down a bit.
     

  3. vafish

    vafish

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    Not an issue.

    The longest 180 gr bullet I could find a length for is the Swift Sirocco at 1.450" (and that is longer than a Barnes all copper TSX). Plugging that into a Greenhill formula calculator I get an optimum twist rate of 1:11".

    A premium 180 gr bullet should work just fine in the .308 for anything up to and including moose and elk. For the big brown and grizzly bears you want more than a .308 anyways.

    Heck if you aren't getting the accuracy you want with a 180 gr bullet a premium 165 gr would work just as well on the big deer like elk and moose.
     
    Last edited: Feb 9, 2010
  4. ju993rnaut

    ju993rnaut

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    snipershide.com(forum) has a ton of info on this...1-11 will be fine for what your going to use it for.
     
  5. Solid Snake

    Solid Snake

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    marines had been using a 1 in 12 twist for years, but i think the newer m40a whatevers will have a shorter barrel and a 1 in 10 twist rate. anyway, that tikka is a good rifle, and a 1 in 11 twist rate is just fine for just about anything 185 grains or less, imho.
     
  6. Clem Eastwood

    Clem Eastwood

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    1:12 stabilizes 168gr match kings without a problem in a 26" barrel. 1:12 even stabilizes 175gr match kings in my rifle. you dont need a 1:10 unless you are planning some 200gr 30-06 bullets in a .308. mostly because of the drop in velocity you will experience because of the loss of case volume from the long bullet.
     
  7. redstar

    redstar Live to shoot

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    Are you a lefty? If you are, I would say that gun is made for you. Tikka's SS is a great gun for the money. It you don't usually shoot left handed, I would recommend against it. Shooting opposite is hard to get used to, and changing eye dominance takes a while.
    Otherwise a 1 in 11 twist is great for anything up to 180 grains, which the 308 typically does not produce barn burner velocities in high grain bullet weights.
    I would also recommend looking at a 7-08. Ultra accurate, short action, same parent case as 308, and wide selection of bullets. 7's usually have 1 in 9 or 1 in 9.5 twist FYI.
     
  8. vafish

    vafish

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    I think the reason for 1:10 being standard in most .308's is a matter of economics more than anything else. The 1:10 is needed for the heavier bullets in the .30-06 and doesn't hurt anything in the .308 so they buy one twist rate barrel blank and use it for both.
     
  9. Clem Eastwood

    Clem Eastwood

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    i hadnt thought about it before because im a .308 guy, but im sure that is the case. because its not like the 1:10 will hurt accuracy in a .308, at least not in a 165gr + bullet, and i bet the lighter bullets would be fine too.
     
  10. PlasticGuy

    PlasticGuy

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    Except that 1:10 is NOT standard for .308 rifles. By far the most common is 1:12, with 1:10 being a distant second and 1:11 being even less common. Any of them will be okay for 147-180 grain bullets, but you'll want 1:10 if you intend to shoot the 190 or 200 grain match bullets or if you intend to shoot any subsonic loads through a suppressor. I like these heavier bullets, but most people don't and would be served just fine with any common .308 barrel.
     
  11. Hound_dogs_01

    Hound_dogs_01

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    So I'm lookign at getting a Savage 10fcp-K with 24" heavy fluted barrel. It has a twist rate of 1:10. So would this be good for my 168gr match bullets as well as 165gr hunting bullets? I may shoot this gun out to 500yards...


    Alex
     
  12. PlasticGuy

    PlasticGuy

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    That would work great for anything from 147-200 grains. Your 165/168 grain loads fall right in the middle of that ideal range.
     
  13. Clem Eastwood

    Clem Eastwood

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    im betting that rifle will shoot really good at 500y. the 165gr sierra game king is so close to the 168gr match king in my 26" remington 700 that i use my 168gr dope (as opposed to my dope for 175gr SMKs) for the 165s.
     
  14. vafish

    vafish

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    From what I've seen 1:10 is at least as popular as 1:12 in the .308 if not more so.

    Here's a list of manufactures and the barrel twist rates they use.

    http://www.exteriorballistics.com/reference/pdf/Twist Tables_Rifle.pdf
     
  15. M1A Shooter

    M1A Shooter

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    for what its worth, the US Army M24 rifles are set up with a 1:11.25" twist which was deemed to be optimized for the M118LR round that shoots a 175grSMK at 2550fps. a 1:12 will do a bit better for the lighter varmint bullets down to 110gr Vmax. the 1:10 will do well up to 180gr or so.

    for the average shooter, it really will not matter. i have a 1:10" barrel on my m14 and it shoots 150gr surplus well and better with a 168gr. i havent tried 175gr bullets in it. my old R700 was a 1:12" and it shot best with my 168gr handloads. shot M118LR decent as well but not as good as my reloads. i havent tried to load the heavy bullets for it though.

    as with anything else, shoot a decent assortment of ammo and see what works best. the same loads form different companies will shoot different in the same gun as well. if you reload your own, you can tailor to the rifle.
     
  16. PlasticGuy

    PlasticGuy

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    That list is out of date.

    I don't believe any Remington 700 is available with a 1:10 twist anymore in any configuration, and Savage has gone away from it with 95% of their rifles also. Ruger has switched to 1:12 twist for everything. That Steyr they list is a limited run model with a short threaded barrel that is optimized for suppressed use with subsonic ammo, and all of their standard models use a 1:12 twist. The Weatherby Vanguard is 1:12 twist now. The Thompson Center bolt actions are the only 1:10 twist bolt actions that I know of that are common and currently in production.

    Again, I like the 1:10 twist so I wish I was wrong. I'm pretty sure my data is accurate though, at least according to the companies' published literature and websites.
     
  17. vafish

    vafish

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    A quick check of Remington's web site and looking at the specifications of their rifles shows a 1:10 twist being used in their .308 caliber rifles in the following models. 7, 770, R25, 750, and 7600. It looks like only the 700 has a 1:12 twist, but I didn't look through all the various models of it.

    I don't have the time to check out every manufacturers web site and the twist rate on the rifle, but I'd say there are plenty of 1:10 twist .308's out there. And I think the reason is pretty much what I already stated, it's more economical to stock one barrel twist rate for the manufacturer.

    But it's kind of silly to continue this in the OP's thread. The answer to his question is that the 1:11 twist on the Tika he is lusting after is just fine. It is probably a very good compromise between the 1:10 and 1:12.
     
    Last edited: Feb 11, 2010