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Thread: Colt SP6920 variations ??????

  1. #31
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    Quote Originally Posted by FChen17213 View Post
    I hope I'm not deviating too far from topic here, but do heavier profile barrels last longer in terms of round count? I know that pencil barrels heat up faster, but also cool faster. For regular semi-auto fire, would a BCM regular profile barrel last longer than a pencil barrel?

    As far as Colt goes, I often wonder why they still make the 6721 with the 1:9 barrel instead of 1:7?
    There really is no proof to show this.

    I hope Colt doesn't make any barrels in 1/9 (as there is no need).


    C4
    Last edited by C4IGrant; 09-05-11 at 09:13.

  2. #32
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    Quote Originally Posted by deadlyfire View Post
    pencil barrels sound like a terrible fad....



    Men took pencil barrels into combat for the first 30 years of the AR-15 existence and everyone got by fine.
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  3. #33
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    Quote Originally Posted by C4IGrant View Post
    There really is no proof to show this.

    I hope Colt doesn't make any barrels in 1/9 (as there is no need).


    C4
    Sorry Grant, but it looks like some of their "Match Target" rifles and all of their "Colt Accurized Rifles" use 1/9 barrels.

    http://www.coltsmfg.com/Catalog/Colt...tchTarget.aspx


    http://www.coltsmfg.com/Catalog/Colt...zedRifles.aspx
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  4. #34
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    Quote Originally Posted by fdxpilot View Post
    Sorry Grant, but it looks like some of their "Match Target" rifles and all of their "Colt Accurized Rifles" use 1/9 barrels.

    http://www.coltsmfg.com/Catalog/Colt...tchTarget.aspx


    http://www.coltsmfg.com/Catalog/Colt...zedRifles.aspx
    Correct. I am hoping that they do not add any more.


    C4

  5. #35
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    Apparently some here have fading memories of the M16 and M16A1.

    Quote Originally Posted by scottryan View Post
    Men took pencil barrels into combat for the first 30 years of the AR-15 existence and everyone got by fine.



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  6. #36
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    I thought the distal end of the barrel being "thickened" was to better withstand sustained full auto fire in the area that barrel heats up most, that's in the distal most end. Is that not true? I seem to remember a video that showed the A2 profile as better withstanding such sustained full auto fire. But I'm guessing that unless one is carrying the IAR, or running and gunning away from a gaggle of Taliban or something, I guess this is a moot point, or unless a thicker overall barell is needed for added stiffness for optimal precision shooting.
    Formerly known as "Son of Vlad Tepes"

  7. #37
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    The ironic part about calling a pencil barrel gay is that from the chamber end to the gas block, the pencil barrel, the gov barrel and the M4 barrel are the same profile. The pencil barrel simply machines away the excess weight the gov & M4 profiles have ahead of the gas block.

    The majority of the heat generated is at the chamber end.

    Stating that the pencil barrel heats up quicker and cools quicker is accurate only so far as when one is talking about temperature. If one were to shoot two barrels until each achieved a surface temperature of say 600 degrees, the lighter barrel would reach that temperature first and would cool down to ambient temperature faster as it is holding less heat than the heavier barrel. It will take fewer rounds for the pencil barrel to reach 600 degrees.

    If one were to shoot an equal amount of rounds in the two barrels, say 500 rounds, the lighter barrel would reach a higher temperature as it has less mass to contain the same BTUs of heat and will suffer heat related wear sooner.

    Lightweight barrels are not gay, lower quality, unreliable or a bad choice. Each barrel profile has it's pros & cons and the compromises each makes is weighted differently. The shooter has to accept the bad along with the good. Remember, TANSTAAFL- There Ain't No Such Thing As A Free Lunch
    Last edited by MistWolf; 09-05-11 at 16:27.
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  8. #38
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    Quote Originally Posted by C4IGrant View Post
    Correct. I am hoping that they do not add any more.


    C4
    Funny thing is, Colt added the 1/9 barrels because of customer demand. There was a period of time that LE and all the cool tactical guys had to have it.

  9. #39
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    Quote Originally Posted by Jake'sDad View Post
    Funny thing is, Colt added the 1/9 barrels because of customer demand. There was a period of time that LE and all the cool tactical guys had to have it.
    More like ARFCOM tacticool guys with BMs who are trying to reduce the size of their .25 MOA groups when shooting M855...

  10. #40
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    The only LE/Tactical carbine that Colt produces with a 1/9" twist, that I'm aware of, is the LE6721, which has a heavy barrel profile as well.
    Employee of colonialshooting.com

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