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Thread: Cold Hammer Forged or not?

  1. #21
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    OP,
    Just my opinion, but I would save up and get the CHF barreled upper. It has zero drawbacks and many benefits should you decide to train more in the future.
    SSG Jimmy Ide- KIA 28 Aug 10, Hyderabad, AFG

    1SG Blue Rowe- KIA 26 May 09, Panjshir, AFG.

    RIP Brothers

  2. #22
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    Cameron pulled the thoughts right out of my head.
    Mike

    I teach for Defensive Response Training in Colorado. We're an OPS affiliate & also host SouthNarc & Progressive Force Concepts.

  3. #23
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    Quote Originally Posted by Cameron View Post
    I'm not sure how a hammer forged barrel outlasts a standard barrel if they are both chrome lined. The heat and friction will eventually wear away the chrome lining, so isn't the hardness of the chrome the relevant component of barrel life?

    As the chrome is worn away the rifling has a less consistent contact with the bullet and you get a degradation is accuracy. The rifle with still work the groups just open up?

    I also don't understand how chrome lining that is twice as think (Noveske) would make a difference. If the rounds wear the chrome lining a measurement of X wouldn't both barrel standard chrome lined and double thickness chrome lined now have the same amount worn? They had to have the same interior dimensions to to start with and in both cases the bullet wears the same amount of chrome, so the interior diameter would be the same...

    Cameron
    Hard chrome is harder than the steel so it last longer. But just because it is harder doesn't mean it will not wear out it just takes longer. If you have x2 chrome lining you are going to have 2x more to go through before you get down to steel.

    CHF barrels are denser because they are hammer forged the rifling, chamber, throat are all forged, The forging also hardens the steel.
    Look what been done to GPMG for extended barrel life thicker chrome lining higher grades of steel hammer forging [originally develop by the Germans in WWII for mass production of MG-42 barrels].

    Look up Stellite-lined barrels cobalt steel lined chamber and throat.
    Cant be much good for accuracy but I am sure it would laaaassst.

    Not the best explanation but i hope it helps.

  4. #24
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    Quote Originally Posted by Thomas M-4 View Post
    Hard chrome is harder than the steel so it last longer. But just because it is harder doesn't mean it will not wear out it just takes longer. If you have x2 chrome lining you are going to have 2x more to go through before you get down to steel.
    I don't like to speak for others but I think what Cameron was getting at and my question as well is even though you have 2x as much hard chrome, the inside diameter of the barrel is still a set value. Once you've worn through the standard thickness of the chrome, yes you would still have more hard chrome before you got to the steel but you've still worn the barrel to the point the ID is no longer the same, thus degraded accuracy. Which would then beg the question, what's the point of the harder cold hammer forging or the 2x chrome lining?

    ETA: I may be way out of my lane here. I'm not an expert gunsmith or metallurgist but I have stayed at a Holiday Inn express before
    Last edited by Icculus; 08-03-10 at 16:07.

  5. #25
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    Quote Originally Posted by Icculus View Post
    I don't like to speak for others but I think what Cameron was getting at and my question as well is even though you have 2x as much hard chrome, the inside diameter of the barrel is still a set value.
    I was thinking the same thing. So would the CHF barrel be more beneficial if it wasn't chrome lining? Cause then the bullet would be having direct contact with the hardened steel and not a chrome coating. I would assume that once the chrome lining has been worn through, no matter what material the barrel is made of, the barrel has then lived its life and accuracy will begin to suffer.

    ...or is the strength of the rifling what makes the life of the barrel, chrome lined or not?

    There's so many dang variables to this

  6. #26
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    Quote Originally Posted by Cameron View Post
    I'm not sure how a hammer forged barrel outlasts a standard barrel if they are both chrome lined. The heat and friction will eventually wear away the chrome lining, so isn't the hardness of the chrome the relevant component of barrel life?

    As the chrome is worn away the rifling has a less consistent contact with the bullet and you get a degradation is accuracy. The rifle with still work the groups just open up?

    I also don't understand how chrome lining that is twice as think (Noveske) would make a difference. If the rounds wear the chrome lining a measurement of X wouldn't both barrel standard chrome lined and double thickness chrome lined now have the same amount worn? They had to have the same interior dimensions to to start with and in both cases the bullet wears the same amount of chrome, so the interior diameter would be the same...

    Cameron
    Quote Originally Posted by Icculus View Post
    I don't like to speak for others but I think what Cameron was getting at and my question as well is even though you have 2x as much hard chrome, the inside diameter of the barrel is still a set value. Once you've worn through the standard thickness of the chrome, yes you would still have more hard chrome before you got to the steel but you've still worn the barrel to the point the ID is no longer the same, thus degraded accuracy. Which would then beg the question, what's the point of the harder cold hammer forging or the 2x chrome lining?

    ETA: I may be way out of my lane here. I'm not an expert gunsmith or metallurgist but I have stayed at a Holiday Inn express before
    You have an acceptable rate of wear that is what a throat erosion gauge is for. Will it still shoot bug eye groups no.. But we are not bench rest shooting neither. Example a few years ago a picked up a MK4 SMLE you can stick a .303 bullet all the way flush to the crown pretty dang wore out and it was also pitted. It would still group 5-8 MOA but it wasn't tumbling the bullets not the best accuracy by any mean. Just trying to point out that it still had some usable life has a spin stabilized bullet spitter. Not that I would want to take anything in that condition into harms way.

  7. #27
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    Cameron has raised a pretty common point when discussing various barrel steels and those different steels when chrome-lined to various thicknesses.

    All I have to offer is that which was passed to me by others in the industry- not by personal testing or verification, and have been relegated to dark and dusty corners of my memory.

    What I recall from the discussion is as follows:

    The thicker the chrome lining the longer it will take erosion, wear, and heat to expose the bare metal beneath the lining. The chrome lining is very thin, even in "double thickness" barrels. Loss of chrome from certain parts of the chamber and throat, while noticably detrimental to high-precision sub-MOA applications, will be transparent to single-digit MOA applications (such as those relevant to a "fighting" AR).
    The harder the underlying metal is, the less the chrome will wear due to heat and friction, though erosion will always be present. Loss of chrome will start at the throat/leade, with decreasing levels of wear the closer to the muzzle you examine. This makes sense when you think about what is happening to the bullet in the barrel at these points. As the bullet engages the rifling it is being mushed by the lands, engaging them with the jacket. As the bullet continues to be pushed by gas expansion the "tracks" of the lands have already been inpressed into the jacket, so now the lands are simply guiding the bullet through existing tracks. Wear at this point is more focused on the edges of the lands than the flats of the lands. Once again, the harder the underlying steel, the less flex will be applied to the surface lining.

    There is also a reasonable point that CHF barrels exhibit more consistent harmonics, including under high heat conditions.

    Another issue is reliability, which really comes down to port erosion. The tougher the steel, the longer it takes for erosion to compromise the gas port.

    Anyway, that's my understanding. I may have left better explainations out, but I did my best to convey my understanding of a topic that isn't really inside my area of expertise.
    Jack Leuba
    Director, Military and Government Sales
    Knight's Armament Company
    jleuba@knightarmco.com

  8. #28
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    The best thing about people jumping on the CHF snake oil bandwagon is lots of great deals on button rifle barreled uppers.
    Kein Mitleid Für Die Mehrheit
    What Happened to the American dream? It came true. You're looking at it.

  9. #29
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    Are there concrete examples, rather than anecdotal, of the CHF barrels lasting longer? I agree with the post above about the extra chrome and the other advantages of the forged barrel.

  10. #30
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    Quote Originally Posted by orionz06 View Post
    Are there concrete examples, rather than anecdotal, of the CHF barrels lasting longer? I agree with the post above about the extra chrome and the other advantages of the forged barrel.
    Its been used in Europe for 50+ years.
    First use was making MG-42 barrels MG-42 were rated at 1200 RPM. It was noted by the Germans that the barrels lasted longer. Not to mention they could make them faster. Than with traditional method's at the time. The MG3 is still made with a CHF barrel, The M-240 has a CHF , The M-249 has a CHF barrel , The AK has a CHF barrel alot of modern military fire arms use CHF barrels.

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