Page 1 of 2 12 LastLast
Results 1 to 7 of 10

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

  1. #1
    Join Date
    Feb 2008
    Posts
    8
    Feedback Score
    0

    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
    Join Date
    Sep 2007
    Location
    AZ
    Posts
    21,926
    Feedback Score
    8 (100%)
    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.
    "You people have too much time on your hands." - scottryan

  3. #3
    Join Date
    Oct 2006
    Location
    TEXAS
    Posts
    1,020
    Feedback Score
    15 (100%)
    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
    Join Date
    Dec 2006
    Location
    Commonwealth of Virginia
    Posts
    3,753
    Feedback Score
    2 (100%)
    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
    Join Date
    Aug 2007
    Location
    PHOENIX AZ
    Posts
    422
    Feedback Score
    0
    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
    give you everything you want, is
    strong enough to take everything
    you have.
    -- Thomas Jefferson

  6. #6
    Join Date
    Feb 2008
    Posts
    8
    Feedback Score
    0
    thanks for th replies.....good info........

  7. #7
    Join Date
    Feb 2008
    Location
    Cambridge MA
    Posts
    115
    Feedback Score
    0
    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

Page 1 of 2 12 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •