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Thread: Standalone barrel that's 4150 or better, HPT and MPI?

  1. #31
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    Quote Originally Posted by jmart View Post
    Thanks for contributing. Would you be willing to discuss your rationale for performing batch testing vs testing every unit?

    Out of the samples of CMV you've tested to date, have any failed your HPT test? If so, what percentage of all batches tested?

    Lastly, would you be willing to share where you source your steel from, and whether or not you mfg the barrels or do you outsource them?
    Some of this I will have to answer when I get into the office later today.

    Our rationale for batch vs individual testing is primarily one of cost and loss of productivity. I mentioned in another thread that if we could raise prices something like 3-5% we would be able to cover the cost. It would slow us down considerably, but we could do it.

    For now I can also tell you that we buy our barrels from either Wilson or Shaw, depending on the build. We specify what material to use and we have certified Material Data Sheets for each specified steel.

    Tomorrow I will let you know the testing results.

    Thanks for your interest in CD Defense products,

    Sincerely,
    Michael Kassnar
    President, K.B.I., Inc.

  2. #32
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    Appreciate your response. Looking forward to the follow up.

  3. #33
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    As I understand it, the HPT and MPI go hand in hand. The HPT is meant to put extreme stress on the part(s), and the MPI is then done to look for problems caused by this stress.

    Doing one without the other does not seem to be as productive to me, although I suppose that the MPI could still find imperfections that exist even without the HPT.

    CD, I'd be interested to know your rejection rates as well if you'd be willing to share. Specifically, I'd like to know if there's a higher rejection rate on the HPT barrels than on the non-tested, if records of that difference are kept.

  4. #34
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    What are your thoughts on just plain old PT? You know, a test firing with a standard 50,000 psi round, followed by the MPI/magnaflux test? I'll concede it's not a HP test, but you're still subjecting those components to 50,000 psi.

  5. #35
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    Quote Originally Posted by jmart View Post
    As an aside, do you have any idea what the reject rates are on the HPT test results for the companies (Colt, LMT) that HPT their CMV mil-spec steel barrels?

    I'm assuming it's less than 1%, but I'm curious when you start with high grade steel to begin with, what the reject rate would be.

    No idea. I do know that in the latest run of BCM barrels, Paul mentioned that he had a couple barrels fail MPI.

    The issue is that each company is going to have a different opinion on what is acceptable and what is not. For instance, several years ago, a Colt barrel was MPI'd and it had flaws in it, but was released to the mass market (on the Civy side of the house).

    One of the very few companies that I know of that does not accept ANY flaws is BCM.



    C4

  6. #36
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    Quote Originally Posted by Charles Daly View Post
    Some of this I will have to answer when I get into the office later today.

    Our rationale for batch vs individual testing is primarily one of cost and loss of productivity. I mentioned in another thread that if we could raise prices something like 3-5% we would be able to cover the cost. It would slow us down considerably, but we could do it.

    For now I can also tell you that we buy our barrels from either Wilson or Shaw, depending on the build. We specify what material to use and we have certified Material Data Sheets for each specified steel.

    Tomorrow I will let you know the testing results.

    Thanks for your interest in CD Defense products,

    Sincerely,
    Thanks for the honest info. It is refreshing to see a manufacturer be so truthful.


    C4

  7. #37
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    Quote Originally Posted by jmart View Post
    What are your thoughts on just plain old PT? You know, a test firing with a standard 50,000 psi round, followed by the MPI/magnaflux test? I'll concede it's not a HP test, but you're still subjecting those components to 50,000 psi.

    Details are really what matters with this stuff. There is a mil-standard way to test this and then there isn't. It is really that cut and dry.

    If Rob want's to make the chart more accurate, the best way to do this is to have manufacturers answer these questions:

    Have the manufacturer issue a detailed and very direct statement as to the chemical composition of their barrels & bolts, the certifications they require, the type of HPT done, what stage it is done, the type of MPI done, the MPI standard followed, the MPI acceptance and rejection criteria their company issues.

    Companies that do NOT give this data, would have their MPI/HPT/Barrel Steel check marks changed.



    C4

  8. #38
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    Mr. Kassnar

    FWIW, since you already have other carbines manufactured to a lower standard than the M4LE, why not go all the way and test every bbl on your best carbine?
    If you really want to sell one of the 2-4 best complete carbines,or complete upper's, then I would follow the TDP as close as I possibly could.
    I hope I'm not off topic, or out of my lane, but from reading your posts, it appears you want to produce and sell the best carbine your company is capable of.
    Good luck, Terry

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