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Thread: Calculate B.C.

  1. #1

    Title
    Premium Member
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    Calculate B.C.

    Anyone know how to come up with a B.C. for a cast bullet?



    Sent from my SAMSUNG-SM-G890A using Tapatalk

  2. #2
    Jay Andrew's Avatar
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    Premium Member
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    Oct 2018
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    168
    If the manufacturer doesn’t list one, there are ways to estimate the BC of a cast bullet.

    There’s Math....if you have something like a Lab Radar you can use the data it produces to come up with a 100 B.C which can be reasonably accurate.

    You can also compare your cast bullet to cast bullet designs which are similar and do list a B.C. value. Which will be reasonably close.

    Then there’s using a ballistic app. If you know the velocity, and you know the bullet drop at a given range. You can use the guess and check method.

    Zero at 100 yards. Shoot at 200 hundred. And three hundred. Measure the drop at both ranges.

    Record the atmospherics.

    Plug in the ballistics app all the data. Find a b.c value that seems like a ball park number for you bullet. Run the chart, see how close it is to the results you shot. If the chart shows it is less then you expected, adjust the B.C value higher. If it’s more, adjust it lower.

    When you have a B.C value you think it is on. Test it. Put a target at 400 yards or at 250, and test a few shots using the table the app generated.

    Probably the easiest poor mans method.




    Reloading...it’s like knitting for men.

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