Quickload fun - 108 Lapuas

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  • richj
    Bloodstained
    • Sep 2014
    • 50

    Quickload fun - 108 Lapuas

    OK I just ordered some 107 SMK and 108 Lap heads. Playing around with QL. Is anyone surprised .
    52k is max but I ran 50k. I picked AR-Comp for the 120 at 26gr. Bold is what I have, sorry but I left out what I can't buy.

  • LRRPF52
    Super Moderator
    • Sep 2014
    • 8569

    #2
    QL is way off in many cases. If you look at Hodgdon's data with actual piezoelectric meter testing:

    28.5C 8208 XBR under 123gr SMK at 2.250" COL is 50,000psi.

    QL says 27.8gr of 8208 XBR under a 108gr Scenar is 50,000psi, which is way off.

    One problem I'm seeing right off the bat that is likely contributing to this is your usable H2O case capacity of 30.3gr, which is much lower than reality.

    Lapua and Hornady brass is 36.5 to 36.2gr of H2O.
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    • JASmith
      Chieftain
      • Sep 2014
      • 1620

      #3
      Ql and the Grendel are frequently not happy campers together. Nonetheless, parametrics like this tend to yield a good estimate of what a particular bullet might do even though the bullet and powder charge weight might be different than the QL result suggests.

      Clearing up confision about QL "Useable Case Capacity" --

      The UC is the volume one gets by subtracting the volume of the part of the bullent below the case mouth from the nominal case volume.

      It looks like the max fill was set to 100% and that limits the performance of slowwer burning powders. CFE 223 is a prome example. Several folks use loads that QL ondicates a filk of 104 to 105% of useable capacity and get highly accurate loads with midest pressures.

      I have tried 106% and higher, but my bullets sometimes creep out after seating so limit CFE loads to 105%.

      One could try a max fill setting of 105% with everything else unchanged and see what happens.
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      Comment

      • Fat Albert
        Bloodstained
        • Feb 2017
        • 36

        #4
        You need to first change the Weighing Factor to .6 and then adj the powder burn rate (BA) up or down to match published pressures. Most BA numbers that come with QL are not even close.

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