QuickLoad velocity and pressure calibration
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  1. #1
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    Default QuickLoad velocity and pressure calibration

    Chris Long discusses calibrating QL with actual velocity data here http://www.the-long-family.com/optim...rel%20time.htm

    Numerous reports of powder being faster or slower are easy to find and my current batch of LilGun does run about 8% faster than QL estimates. (not a 6.8)

    My question is if, after adjusting the burn rate in QL to match Magnetospeed velocity, is the pressure then reported by QL fairly accurate?



  2. #2
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    Quote Originally Posted by pnw View Post
    Chris Long discusses calibrating QL with actual velocity data here http://www.the-long-family.com/optim...rel%20time.htm

    Numerous reports of powder being faster or slower are easy to find and my current batch of LilGun does run about 8% faster than QL estimates. (not a 6.8)

    My question is if, after adjusting the burn rate in QL to match Magnetospeed velocity, is the pressure then reported by QL fairly accurate?



    Your thoughts?

  3. #3
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    i play with powder burn rate and weighting factor to dial quick load in to giving more accurate pressure readings. i also have pressure trace so that also helps.

    you are on the right track.

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  5. #4
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    Quote Originally Posted by biggdawg View Post
    i play with powder burn rate and weighting factor to dial quick load in to giving more accurate pressure readings. i also have pressure trace so that also helps.

    you are on the right track.
    Exactly what BiggDawg said...
    I don't have the pressure trace - but have revised powder burn rate, and tweaked weighting factor to dial in QL.
    Normally find that QL burn rate - after updating, will predict velocity within 20fps of my Oehler 35p, and sometimes in single digits.

  6. #5
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    Quote Originally Posted by Homebrewer View Post
    Exactly what BiggDawg said...
    I don't have the pressure trace - but have revised powder burn rate, and tweaked weighting factor to dial in QL.
    Normally find that QL burn rate - after updating, will predict velocity within 20fps of my Oehler 35p, and sometimes in single digits.
    Do you mean the Ba factor that you revise? I use that to find a powder that is similar to the surplus powders I sometimes use, which of course, are not on the powder list in QL. And what is the weighting factor?...

    Thanks...BCB

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    Quote Originally Posted by BCB View Post
    Do you mean the Ba factor that you revise? I use that to find a powder that is similar to the surplus powders I sometimes use, which of course, are not on the powder list in QL. And what is the weighting factor?...

    Thanks...BCB
    Quick Load - Burning Rate Factor = Ba, is the powder burn rate to revise up to 10% ( +/- ) of the original QL value.
    -
    Weighting Factor in QL is a number to represent the fraction of unburned powder and propellant gases that follows the bullet in the bore.
    Reasonable default values for weighting factor - from QL:
    0.75 for cylindrical cases
    0.50 for typical bottleneck cases
    0.33 for "overbore" bottleneck cases...

  8. #7
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    Quote Originally Posted by Homebrewer View Post
    Quick Load - Burning Rate Factor = Ba, is the powder burn rate to revise up to 10% ( +/- ) of the original QL value.
    -
    Weighting Factor in QL is a number to represent the fraction of unburned powder and propellant gases that follows the bullet in the bore.
    Reasonable default values for weighting factor - from QL:
    0.75 for cylindrical cases
    0.50 for typical bottleneck cases
    0.33 for "overbore" bottleneck cases...
    O.K. I probably won't use the weighting factor...

    But, I do change the Ba from time to time as I use some surplus powder that is recommended to be loaded using certain other powder's data. I use equal charge of the recommended powder and the surplus powder. By shooting them both over a chrony, I can then adjust the Ba of the recommended powder to use as data for the surplus...

    Thanks...BCB


 

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