Retumbo and barrel length

Discussion in 'Reloading' started by Earnhardt, Sep 23, 2012.

  1. Earnhardt

    Earnhardt Well-Known Member

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    I'm using Retumbo for the first time, and had a few questions.
    For loads of 100 grains or more, is there a minimum barrel length that a guy should have to allow the powder to fully burn?
    26", 28", 30"?

    Guns are a .30/378 and .416.

    Thanks
     
    Last edited: Sep 23, 2012
  2. elkaholic

    elkaholic Well-Known Member

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    There have been tests run which show that to FULLY burn ,you need at least 36", depending on powder. I wouldn't worry whether or not it was 26" or 30" except you will lose approx. 40'/sec for every inch.......Rich
     

  3. Robinhood493

    Robinhood493 Well-Known Member

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    In my .300 RUM with a 26" barrel with a brake, anything over 102g of Retumbo doesn't have any more velocity increase. I am assuming that it is reaching the point where there it too much podwer to burn completely in a 26" barrel. I could be wrong though, just my opinion.
     
  4. elkaholic

    elkaholic Well-Known Member

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    I don't know what bullet weight that is with but you could pushing chamber pressure as well! Once you reach a certain point, velocity will not increase much......rich
     
  5. Robinhood493

    Robinhood493 Well-Known Member

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    It is with 180g Partitions. I get very very slight ejector marks at temps above 90 degress with 103g.
     
  6. elkaholic

    elkaholic Well-Known Member

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    Probably dropping off from too much pressure.......Rich
     
  7. g0rd0

    g0rd0 Well-Known Member

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    barrel lenght and powder are moot unless you know your expantion ratio. Once you know your expantion ratio (ER) then you can choose the best powder for your rifle.