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Thread: Twist rates for various calibers?

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  1. #1
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    Twist rates for various calibers?

    I need some help with deciding which direction to go. I am wanting to do some medium range work and learn something new. I have no experience shooting past 200yds and have decided to finally scratch the itch to do some "longer" shooting. Max range will be only 400/500yds. I want to stay with .223 for sure, however everything I find has a twist rate of 1/9. Will that twist work with the heavier bullets in the bolt gun? I'm not wanting to re-barrel from a factory gun to get the twist I need, if thats the case, I'll stick with my AR's. Thanks for the help guys!

  2. #2
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    1/7 & 1/8 are considered the prefered twist for what you want to do...

    1/9 with 75gr & up is a crap shoot.
    "You cannot invade the mainland United States. There would be a rifle behind each blade of grass."
    Japanese Admiral Yamamoto, 1941




    "A wise man's heart directs him toward the right, but a foolish man's heart directs him toward the left."
    Ecclesiastes 10:2:

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    Thanks for the reply. Whats up with no one making the 1/7 twist standard for these? Oh well, appreciate the help!

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    Quote Originally Posted by Quick Stick View Post
    Thanks for the reply. Whats up with no one making the 1/7 twist standard for these? Oh well, appreciate the help!
    Just my opinion....but it seems that manufacturers making .223 bolt guns do so with the intended purpose of varmit hunting. Typically a bullet weight of 40 to 50 grains is used for this....and the bullet velocity is notably faster than what the 75 to 90 grain bullets produce. As such, barrels with slower twist rates are put on these bolt action rifles.

    I'm not claiming that any logic from the manufacturer is being applied here...but that is how it appears so me. Maybe someone else has an idea?
    Last edited by arizona98tj; 02-22-12 at 20:26.

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    Quote Originally Posted by arizona98tj View Post
    Just my opinion....but it seems that manufacturers making .223 bolt guns do so with the intended purpose of varmit hunting. Typically a bullet weight of 40 to 50 grains is used for this....and the bullet velocity is notably faster than what the 75 to 90 grain bullets produce. As such, barrels with slower twist rates are put on these bolt action rifles.

    I'm not claiming that any logic from the manufacturer is being applied here...but that is how it appears so me. Maybe someone else has an idea?
    I agree with your logic

  6. #6
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    If barrel length is 22-24", 1 in 9" might stabilize 75-77 grain bullets given the added velocity. If barrel is shorter, you need to look for 1 in 8" or quicker to be safe.

    I'd pose this question at Sniperhide or 6mmBR.com to get an answer from folks who have probably plowed this ground before. Asking a predominantly carbine board won't get you much "hands on" advise.
    Last edited by jmart; 02-22-12 at 22:04.

  7. #7
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    1:9 will shoot 69gr bullets perfectly fine out to 400/500yds. Give them a try.

    Sent from my DROIDX using Tapatalk

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    Savage 12FTR (Target Rifle Series) has a 1:7 twist rate. http://savagearms.com/firearms/models/
    Last edited by CRT2; 06-16-13 at 09:13.

  9. #9
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    I have become a firm believer of faster twist rates, especially on shorter barrels. 1/8 is a good rate for 16" .308's.

  10. #10
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    It's a question of simple math why shorter barrels benefit from a faster twist rate to maintain stability despite their lower muzzle velocities.

    A bullet needs a certain rotational velocity to remain stable thoughtout its flight.

    I'm going to extremely oversimplify the physics because I am going to assume the bullet reaches full MV essentially as it leaves the cartridge.

    In that case, the bullet's rotational velocity in revolutions/second is simply the product of the rifling rate (expressed in revolutions/inch) and muzzle velocity (in inches/second).

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