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Thread: 1/7 or 1/9 barrell twist..???

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  1. #1
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    1/7 or 1/9 barrell twist..???

    Is there a signifigant difference between 1/7 and 1/9 twist? And if so what is the effect, and should a AR novice really care? I'm sure this has been question has been beaten to death on this forum so thanks for the info in advance.......

  2. #2
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    If you want to shoot anything over 69 grains get a 1/7. I have no need for that so most of my barrels are 1/9.

    I run a few 1/7s but that is only because some barrels only come in that twist.
    "What would a $2,000 Geissele Super Duty do that a $500 PSA door buster on Black Friday couldn't do?" - Stopsign32v

  3. #3
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    Quote Originally Posted by moresky View Post
    Is there a signifigant difference between 1/7 and 1/9 twist?
    That depends on wat you consider significant. The 1/7" twist will handle the heavier bullet weights.


    Quote Originally Posted by moresky View Post
    And if so what is the effect
    If the twist is too slow for the load, you'll get key-holing, i.e. the bullet will start to tumble during it's trajectory.

    Quote Originally Posted by moresky View Post
    should a AR novice really care?
    Probably not. The AR novice in all likelihood would be sticking to 55grn and 62grn rnds that the 1/9"can handle

    Quote Originally Posted by moresky View Post
    I'm sure this has been question has been beaten to death on this forum so thanks for the info in advance
    Not sure if it's been beaten to death here but it has elsewhere

  4. #4
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    Just to add, I regularly shoot 75-grain Match ammo (Black Hills) out of my Bushy Varminter which has a 1/9 twist barrel. I have hit a 10-inch plate with this out to 926-yards and if I were to do my part (which is very rare), it would put the round after round into the same hole at 100-yards. FWIW.
    We must not believe the Evil One when he tells us that there is nothing we can do in the face of violence, injustice and sin. - Pope Francis I

  5. #5
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    If you have the choice ,get a 1/7. 75 and 77 grain preform well with a 1/7 twist .the Hornady 75 tap and the 77 SMK rounds are the trend for SD and a lot of PD's use the .556 Hornady tap as thier day to day ammo . get the 1/7 use 75 and 77 grain ammo ,better range,and better stopping power .
    WHO ME ? ---- A government big enough to
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  6. #6
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    thanks for th replies.....good info........

  7. #7
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    I just sold my upper and built another just for a 1/7" twist barrel.

    Both will shoot 55gr. ammo just fine.

    Some 1/9" will shoot the latest/greatest 77gr. defensive ammo, but some don't.

    I wanted the 1/7" so I could shoot 77gr.

    Plus, most of the 4150 CMV barrels out there only come in 1/7" twist

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