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Thread: Is 1/9" twist a deal breaker?

  1. #71
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    Twist rate has nothing to do with the terminal performance issues, as noted here: http://www.dtic.mil/ndia/2008Intl/Roberts.pdf. Tests have been conducted using 1/14, 1/12, 1/9, 1/7 barreled M16's firing 55 gr M193 FMJ and no difference in terminal performance was noted. In addition, the twist rate necessary to stabilize projectiles in air has little to do with the rate necessary to stabilize them in tissue.
    Last edited by DocGKR; 03-09-10 at 15:37.

  2. #72
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    Quote Originally Posted by DocGKR View Post
    Twist rate has nothing to do with the terminal performance issues, as noted here: http://www.dtic.mil/ndia/2008Intl/Roberts.pdf. Tests have been conducted using 1/14, 1/12, 1/9, 1/7 barreled M16's firing 55 gr M193 FMJ and no difference in terminal performance was noted...
    Thanks for the read.

  3. #73
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    Quote Originally Posted by dcollect View Post
    No doubt about that. For my application I find the 1/7" twist excessive. Personally, if I found a 1/14" twist barrel in my profile - it would be on my rifle.
    Have a 1x12 colt sp1 like NIB I will sell you

  4. #74
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    1x9 twist

    I dont understand do you buy several thousand rounds of 55gr to practice with at range and and use mk262 as hd/pd .

    It seems ATK federal 62gr bonded was proven to be best PD load available great choice for 1x9

    If 1x9 is what you have what difference does it make if it does,nt stabalize 75 and up past 100 yds or even 50 for that matter home defence is room to room.

    I cant afford to practice with 75gr tap or equivalent at $1500.00 1000 RDS

    But 55gr PMC and equivalent ammo at $350.00 to 400.00 per 1000 is a different story

  5. #75
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    Quote Originally Posted by dcollect View Post
    1/7" was introduced to stabilize M865 tracer.

    If you're not shooting tracer, you'd be better served by 1/8" for the heavier rounds.
    Depends on barrel length. For 75/77 in a 10-16 inch I would still think 1:7 is more appropriate. If 1:7 gave up accuracy with 55 grain bullets it would likely be less than 0.1 MOA difference.

    Quote Originally Posted by dcollect View Post
    The least spin you can put on a projectile while maintaining it's stability is preferred
    Only once you account for all conditions, such as the longest bullet that may be used, -20 degrees F and low altitude, and enough stability to never baffle strike a can.

    It is frustrating to see people say how great TAP 75 works in their 1:9 twist rifle and then find out they live in Colorado at 6000 feet and they tested it on an 80 degree day.

  6. #76
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    Quote Originally Posted by newguy View Post
    I dont understand do you buy several thousand rounds of 55gr to practice with at range and and use mk262 as hd/pd .

    It seems ATK federal 62gr bonded was proven to be best PD load available great choice for 1x9

    If 1x9 is what you have what difference does it make if it does,nt stabalize 75 and up past 100 yds or even 50 for that matter home defence is room to room.

    I cant afford to practice with 75gr tap or equivalent at $1500.00 1000 RDS

    But 55gr PMC and equivalent ammo at $350.00 to 400.00 per 1000 is a different story
    I only have the guys shoot 75 grain Tap for the qualification. All training is done with 55 grain ball. There is not enough of a difference in point of impact to matter. You don't have to shoot what you carry all the time. Just enough to make sure its reliable in your weapon and to know where it hits.
    Pat
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  7. #77
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    Practically speaking, in a HD or CQB scenario, does twist really even matter? Shouldn't we be more worried about shot placement and training? A noggin cares not whether it is split by 55gr, 62gr, 75gr, 77gr, or even 36gr from my .22 conversion kit, it's still split. No heavier bullets, faster twist, or more stopping power needed if you get good shot placement. And the differences seen in the 1/7 vs the 1/9 won't really become evident until after 100yds right? That being said, I have a 1/7 twist, cold hammer forged, chrome lined barrel.

    I just think we split hairs over the craziest things sometimes, when the OP just needs to get a good quality rifle and get out to shooting it and forget about the twist.

  8. #78
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    Quote Originally Posted by dcollect View Post
    1/7" was introduced to stabilize M865 tracer.

    If you're not shooting tracer, you'd be better served by 1/8" for the heavier rounds.

    The least spin you can put on a projectile while maintaining it's stability is preferred.
    Yeah, but 1/8 twist barrels are rarely chrome plated nor are they readily available or affordable. Let's be realistic and keep the OP's RFI in mind here.

    My carbines are all 1/7-twist and I don't find it "excessive" at all? I practice with nothing but 55-grain FMJ but my real world ammo ranges in weight from 55-grain thru 77-grains of various bullet types (the right tool for the right problem). They all stabilize and deliver the accuracy I need out of my Carbines. JM2CW.
    Last edited by CarlosDJackal; 03-10-10 at 19:00.
    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

  9. #79
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    Quote Originally Posted by rav3nwulfe View Post
    Practically speaking, in a HD or CQB scenario, does twist really even matter? Shouldn't we be more worried about shot placement and training? A noggin cares not whether it is split by 55gr, 62gr, 75gr, 77gr, or even 36gr from my .22 conversion kit, it's still split. No heavier bullets, faster twist, or more stopping power needed if you get good shot placement. And the differences seen in the 1/7 vs the 1/9 won't really become evident until after 100yds right? That being said, I have a 1/7 twist, cold hammer forged, chrome lined barrel.

    I just think we split hairs over the craziest things sometimes, when the OP just needs to get a good quality rifle and get out to shooting it and forget about the twist.
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  10. #80
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    Quote Originally Posted by CaptainDooley View Post
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