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

  1. #21
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    Quote Originally Posted by jaxman7 View Post
    Alright guys here's another question to bring up with the different twist rates....Is there any substantial difference in the round tumbling when it hits soft tissue? In theory the 1/9 would be a better candidate for this because it is less stable if using the same weight bullet in both 'twists' of barrels. If I recall correctly the original m16 came with a 1/12 twist and when the initial end users in Vietnam (army SF) returned to the states they recounted excellent results that were directly related to the instability of the round. As the military has gradually fastened the twist rate the reports of so called stopping power has decreased at the same rate. Granted most of us do not have to abide by the ridiculous Hague accord that mandates nonexpanding rounds. Would love to hear your feedback fellas.



    M193 worked in Vietnam because the engagement distances were usually very short, and within the fragmentation rage of the round being used.


    In places like Iraq, and specifically Afghanistan the ranges are much longer so that "effect" isn't the same, and we are now using a round with a steel core.



    You are right. LE and civi's are not limited to the rounds we use, and we have much better offerings than what mil has in general issue. My HD/SD ammo is MK262mod1 which is is a mil round which has generated very positive reports in both lethality and accuracy.


    I am also interested in the 70GR Barnes TSX loading SSA has out which is a copper solid. Its a successful round in the hunting community which means it will work on two legged animals well. I have not gotten the chance to get any yet but will shortly.
    Last edited by Belmont31R; 03-04-10 at 20:50.

  2. #22
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    Very good point bud. I am interested as well in the Barnes load. My home defense ammo now is hornady t.a.p. in 75 grain with a DD 1/7 barrel. I've just always been curious in the difference in projectile stability between 1/7 and 1/9.

  3. #23
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    Quote Originally Posted by jaxman7 View Post
    Very good point bud. I am interested as well in the Barnes load. My home defense ammo now is hornady t.a.p. in 75 grain with a DD 1/7 barrel. I've just always been curious in the difference in projectile stability between 1/7 and 1/9.


    What I do know is 1/7 works with 55-77+ which is the range of ammo I shoot.


    1/9 is very spotty (unreliable) in the 70+ range which is what match and HD/SD ammo I use is. Therefore I see no reason to buy a 1/9 barrel.



    1/8 is also fine in the 70+ range. Im on my 2nd stealth upper (1/8), and they shoot 77GR just fine....

  4. #24
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    Me too Belmont I use bullets ranging between 55-75 grain as well. One thing else to remember is that when I use the longer/heavier rounds I run into the problem of a failure to feed in a barrel not equipped with an M4 feedramp. Just something else to consider in choosing a twist rate. There are a lot more companys out there offering M4 feedramps with a 1/7 twist as opposed to a 1/9. Just something else to consider.

  5. #25
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    Quote Originally Posted by scottryan View Post
    The more important thing here is you do not need a piston system for this gun especially since this is your first AR15.
    First OR Last AR... there's no reason for a piston AR...

    A piston also brings a number of negatives into play such as more weight, more complicated moving parts, proprietary parts, and a decline in accuracy.
    It's ironic that people think by introducing a bunch of extra moving parts that they're getting more reliability.... not to mention all of the design flaws in all of these systems...

    My idea is to replace all those ****ed up parts with a Stainless steel gas tube that won't break or seize up.
    Last edited by markm; 03-04-10 at 22:15.

  6. #26
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    Quote Originally Posted by KalashniKEV View Post
    I'm confident in 55gr FMJ for defensive purposes, anything heavier, or engineered just impoves your margin of lethality.

    It's debatable, IMO.

    What isn't debatable is performace at a distance, in which case heavier is definitely superior.
    You really need to take a look at the ballistic forum on this site.
    https://www.m4carbine.net/forumdisplay.php?f=91

    There is a huge difference in stoppng power between 55 grain ball and 77 grain OTM.
    Pat
    Last edited by Alaskapopo; 03-05-10 at 01:00.
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  7. #27
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    Quote Originally Posted by Alaskapopo View Post
    You really need to take a look at the ballistic forum on this site.

    Pat
    I've seen it.

    I just don't buy into "margins of lethality" and 77>62>55 + 14.5">12.5">11.5">10.5"...

    As I've said before there are a lot of factors at play when a bullet enters soft tissue, you're not going to convince me that the effectiveness or ineffectiveness of solid hits in the primary lethal zone rests on whether the bullet is 55 or 77 grains.

    For the OP's specifications, primary use-range, primary ammo 55gr, my recommendation remains 1/9.

  8. #28
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    Quote Originally Posted by KalashniKEV View Post
    I've seen it.

    I just don't buy into "margins of lethality" and 77>62>55 + 14.5">12.5">11.5">10.5"...

    As I've said before there are a lot of factors at play when a bullet enters soft tissue, you're not going to convince me that the effectiveness or ineffectiveness of solid hits in the primary lethal zone rests on whether the bullet is 55 or 77 grains.

    For the OP's specifications, primary use-range, primary ammo 55gr, my recommendation remains 1/9.
    With respect there is a huge difference. If you have truely looked at Dr. Roberts data you would understand that.
    Pat
    Serving as a LEO since 1999.
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    Armorer for AR15, 1911, Glocks and Remington 870 shotguns.

  9. #29
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    Quote Originally Posted by markm View Post

    It's ironic that people think by introducing a bunch of extra moving parts that they're getting more reliability.... not to mention all of the design flaws in all of these systems...

    My idea is to replace all those ****ed up parts with a Stainless steel gas tube that won't break or seize up.
    +1!!!

    "Addressing the problem of shootings by ban or confiscation of non-criminal's guns is like addressing the problem of rape by chopping off the Johnson of everyone who DIDN't rape anyone while not only leaving the rapists' equipment intact, but giving them free viagra to boot." --Me

  10. #30
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    Quote Originally Posted by jaxman7 View Post
    Alright guys here's another question to bring up with the different twist rates....Is there any substantial difference in the round tumbling when it hits soft tissue? In theory the 1/9 would be a better candidate for this because it is less stable if using the same weight bullet in both 'twists' of barrels. If I recall correctly the original m16 came with a 1/12 twist and when the initial end users in Vietnam (army SF) returned to the states they recounted excellent results that were directly related to the instability of the round. As the military has gradually fastened the twist rate the reports of so called stopping power has decreased at the same rate. Granted most of us do not have to abide by the ridiculous Hague accord that mandates nonexpanding rounds. Would love to hear your feedback fellas.
    Not sure about the twist of the Vietnam A1, but if the engagements were in heavy jungle (before the Agent Orange had fried much of the vegetation) simply hitting branches between the target and the muzzle could be a reason for bullets tumbling as much as anything else. Just speculating.

    "Addressing the problem of shootings by ban or confiscation of non-criminal's guns is like addressing the problem of rape by chopping off the Johnson of everyone who DIDN't rape anyone while not only leaving the rapists' equipment intact, but giving them free viagra to boot." --Me

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