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Thread: Relocating Gas Port

  1. #21
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    Quote Originally Posted by OldState View Post
    Understood. And I don't expect a chrome lined non-free floated barrel to be super accurate...but there are also thermal benefits of more mass. Don't you fire a lot of ammo in a carbine class, etc?

    I will give it another look. The price of 6920's seems to have gone up over the weekend. To bad the wife gave me the go-ahead Saturday night.
    ======================================

    There are other AR's that will serve you well at that price range AND you can get them in Mid-Length actions.
    Take a look at The Chart and see what you find.

    .

  2. #22
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    Quote Originally Posted by C4IGrant View Post
    Uhm no. Thin barrels cool down faster than thick barrel.
    C4
    But they likewise heat up faster and get hotter with fewer rounds. This could effect accuracy and the life of the barrel as metal only gets softer the hotter it gets. Wouldn't the gov't barrel be a happy medium?
    I thought that is why the pencil barrels were dropped from m16's.

    Then again I may never fire enough at one time for this to mater.

  3. #23
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    Quote Originally Posted by ucrt View Post
    ======================================

    There are other AR's that will serve you well at that price range AND you can get them in Mid-Length actions.
    Take a look at The Chart and see what you find.

    .
    That was my original plan but since the 6920 was selling for $1099 recently, I figured I might as well get the Colt nostalgic/resale reasons.

  4. #24
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    Quote Originally Posted by C4IGrant View Post
    Uhm no. Thin barrels cool down faster than thick barrel...

    C4
    Heat isn't just about temperature, it's about the amount of heat the barrel has absorbed. Barrels with less mass reach higher temperatures because the heat is more concentrated. With the raised temperatures, the barrel is more susceptible to heat damage. Added to that is barrels of less mass and of the same length (assuming both are circular) have less surface with which to radiate heat.

    If one were to shoot two barrels, one massing 1lbs and the other 2lbs, it would take more heat (more rounds fired) to bring the 2lbs barrel to a temperature of 200 degrees. With both barrels heated to 200 degrees, it would take the 2lbs barrel longer than the 1lbs barrel to cool to ambient temperatures because it's holding more heat.

    However, if both barrels were subjected to the same amount of heat (measured in joules, BTUs or other unit of energy), the 2lbs barrel would have a lower temperature than the 1lbs barrel.

    This does not mean the pencil barrel is not a good choice for a carbine. A light-weight fast handling carbine is a joy. It just means like everything else in life, barrel mass is a trade-off. In this case, I would choose the fast handling qualities of the light barrel over the thermal advantages of the heavy barrel.

    Also, quality light-weight barrels are very accurate
    Last edited by MistWolf; 02-14-11 at 17:32.

  5. #25
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    I wonder what the weight difference is.

  6. #26
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    All barrels will get hot if you shoot them enough, and there is not a huge difference between government and lightweight. I'd rather have a lightweight barrel with a good rail that allowed for air to circulate than a heavier barrel under standard handguards or a crappy rail.

  7. #27
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    The .gov profile makes little sense to me. It's thicker at the muzzle where the mass does no good controlling the heat at the critical area of the throat. Putting the extra weight at the muzzle only increases the arm, making it harder for the shooter to change directions with the rifle.

    What was the original intention of the .gov profile barrel?

  8. #28
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    In theory the misplaced mass at the end of the barrel on a government profile could make the barrel more likely to droop.

    In theory.
    We miss you, AC.
    We miss you, ToddG.

  9. #29
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    I think the whole mid vs. car gas system debate is a bit over blown. How long have mid-length guns been out in any great quantity? 2 years? I know when I got my DDM4 in 08 I dont think there was such a thing as a mid-length gas system(or at least it wasnt popular).

    I am not saying the mid-length system is not good, but people make it seem like the car system is so terrible that people are staying away from it.

    I have shot both. I personally didnt notice a huge difference. If the CAR system beats up parts a little more than a MID, I dont know, maybe.

    I would not hesitate to buy a gun in either form if it was setup how I wanted it.

  10. #30
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    Ive been happy with the carbine gas system for along time now.
    Havent ran into any problems.

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