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Thread: Why don't more manufacturers offer 1:7 rifling twist?

  1. #21
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    I know that I took a 1/7 & 1/9 twist rifle to the range one day and was shooting the orange tip tracers at 400 to 500 yards. With the 9 twist at about 200 to 300 yards the bullets would act as if they had a mind of their own and would fly off in all directions, some even went straight up. The 7 twist would send them where I shot them.

  2. #22
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    Quote Originally Posted by Hootiewho View Post
    I know that I took a 1/7 & 1/9 twist rifle to the range one day and was shooting the orange tip tracers at 400 to 500 yards. With the 9 twist at about 200 to 300 yards the bullets would act as if they had a mind of their own and would fly off in all directions, some even went straight up. The 7 twist would send them where I shot them.
    Not surprising. 1/9 twist barrels and heavier bullets tend to shoot patterns instead of groups at long distances.



    C4

  3. #23
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    NATO went with 1/7 and the heavier bullet to help penetration of lightly armored targets, however it was a less lethal round. The 55gr bullets out of a 1/12 or 1/14 M16 killed people better because it was so unstable,this also cause a problem for some of the kind hearted Europeans. RH

  4. #24
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    Quote Originally Posted by AR15barrels View Post
    Barrel length is an issue here.
    In 20" barrels, no problem.
    In 10.5" barrels, the 80's are right on the edge.
    The 77's should be fine in 10.5" 1:8's though.
    Can 80's be loaded to mag length?

  5. #25
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    Quote Originally Posted by jmart View Post
    Can 80's be loaded to mag length?
    I cut a notch in several of my 20rd mags that allow me to load two 80gr handloads for high power competition. The OAL of my loads will not fit in a standard magazine.

  6. #26
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    Quote Originally Posted by DRich View Post
    I cut a notch in several of my 20rd mags that allow me to load two 80gr handloads for high power competition. The OAL of my loads will not fit in a standard magazine.
    That's what I thought. The dsicussion of using 80's in carbines/SBR's for self defense is kind of a moot point. Unless you are willing to single load them during your firefight.

  7. #27
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    Quote Originally Posted by jmart View Post
    That's what I thought. The dsicussion of using 80's in carbines/SBR's for self defense is kind of a moot point. Unless you are willing to single load them during your firefight.
    The only 80's I've used are Berger VLD's. The Sierra or Nosler 80gr bullets may have a different ogive that allows them to be seated deeper in the case and allow them to fit in a standard mag. I just don't have any experience with them.

  8. #28
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    I'm still amazed on how dumb manufacturers are. The 1:8" twist is the absolute perfect all around twist for the AR, yet no one makes a chrome line 1:8" twist except CMMG with the 18" barrels. You can shoot 45-80 Gr. bullets with the 1:8" twist. What else do you want? The 1:12" twist is ideal for the 35-60 Gr. bullets.

    The 1:7" twist is best for the military because of the length of the tracers.

  9. #29
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    Quote Originally Posted by RHtx View Post
    NATO went with 1/7 and the heavier bullet to help penetration of lightly armored targets, however it was a less lethal round. The 55gr bullets out of a 1/12 or 1/14 M16 killed people better because it was so unstable,this also cause a problem for some of the kind hearted Europeans. RH
    Utterly false.
    M855 frags the same way M193 does

    Stability in tissue is nothing like stability in air -- please check your facts.
    Kevin S. Boland
    Manager, Federal Sales
    FN America, LLC
    Office: 703.288.3500 x181 | Mobile: 407-451-4544 | Fax: 703.288.4505
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  10. #30
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    Thank you Kevin!!!! That one isn't even Internet baloney; it was already deeply entrenched back when all we had were books (remember those?) about guns.

    I shoot 77 SMK, 77 Nosler, 75 whatevers with no problem in both my 1:8 match AR and 1:9 M&P-15. I've only shot the M&P as far as 100 yards though.

    Hornady 75 AMAX, which is long and skinnier than the 80s, works fine in the 1:8 match AR out to 800. At 900-1000 with service-length barrel, even the mighty AMAX over primer-flattening loads of RL-15 will start to go subsonic and keyhole, according to the guys pulling my target the only time I tried it.

    I haven't tried the Berger 90 VLDs at all, or any over-mag-length load in my M&P. When my barrels wear out, I'll put 1:7s on both of them and be done with it.
    When life gives you lemons, insert copper and zinc wires in them and repeatedly shock your tongue.

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