A small contribution to the shooting community

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Eaglet, Apr 12, 2010.

  1. Eaglet

    Eaglet Well-Known Member

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    lightbulb A SMALL CONTRIBUTION TO THE SHOOTING COMMUNITY lightbulb

    I have created a small application that uses most of the equations found in
    the book Applied Ballistics for Long Range Shooting by
    Bryan Litz
    I find it very useful and it sure is a great tool to get very close values for BC7, BC1
    from measurements of a long range bullet. There are various equations that are
    fun to use.

    It's a very simple straight forward application that would be useful for some of the
    long range shooting addicts. :)

    It's only for the Windows Platform, unfortunately.

    Download the zipped file named "readme.zip". When you unzip it there will be two
    files, one is the ".exe" application and the other one is the readme.text file.

    Please read the short readme.text file before you run it.

    You don't have to install it; I recommend you drop the ".exe" file on your desk top
    and your ready to go after checking the readme.text file.
    **************************
    Version 2.0.0.0 is out!!!! Link below was changed.
    ****************************
    http://pages.sbcglobal.net/jomoncada/Eaglet_Ballistics/eaglet_ballistics.zip

    Those interested in receiving updates please e-mail me at Javier_Moncada@yahoo.com
    In the Subject box write: Eaglet Ballistic Calcs

    Those that received this as an e-mail will automatically receive the updates, but
    if you are not interested just e-mail me and I will remove you from the mailing list.

    As a man of honor and a minister I assure you your e-mails will only be used by others
    if I get killed first!

    Sincerely,

    Javier O Moncada
     
    Last edited: May 11, 2010
  2. Eaglet

    Eaglet Well-Known Member

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    Changes have been made to allow the application to run
    in smaller resolution screens. Just download it from the
    same link above and replace the old file with the new.
     

  3. Mikecr

    Mikecr Well-Known Member

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    Where do we get RT/R?
     
  4. Eaglet

    Eaglet Well-Known Member

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    Mikecr, good question!

    I will tell you how I do it.

    I know is a value between 0.5 and 1.0 by studying the bullet diagrams on

    Bryan Litz's book, I can get pretty close at guessing the number. I have tested

    my self and as the book states it, it can easily be done. It also states

    how difficult it is to calculate it. You might find some info. on line that would be

    useful. What we need to keep in mind is that we don't have a whole lot to

    err with, we'll go from 0.5 to 1.0 being 1.0 perfectly tangent ogive radius.

    By looking at the bullets diagrams and seeing their Rt/R ratio values and how

    they change in value as the bullet ogive changes you get a pretty good idea of

    what you're doing.

    I know I'm not giving you what you want to hear, but with a bit of practice

    one can really get close to calculating them BC7s.

    There is a whole lot to learn about that stuff! :D
     
  5. Mikecr

    Mikecr Well-Known Member

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    I'll keep looking.
    May need a tool(laser mic) & software to derive it...
    Wonder how Bryan obtained RT/R
     
  6. Eaglet

    Eaglet Well-Known Member

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    Last edited: Apr 14, 2010
  7. phorwath

    phorwath Well-Known Member

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    Very convenient. Thanks for sharing the benefits of your work product!
     
  8. Eaglet

    Eaglet Well-Known Member

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    phorwath,

    You are very welcome!

    And Thank You again for the kind help you provided for me!
     
  9. BryanLitz

    BryanLitz <b>Official LRH Sponsor</b>

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    I wouldn't wish my tedious method on anyone.

    First step is to mount the bullet in a lathe and indicate the bullet ogive with a dial indicator every 0.025" along it's surface. Then input those coordinates into a computer program that calculates ogive radius and length. Then calculate the radius of a perfectly tangent ogive of that length. Finally, divide the 'perfectly tangent' ogive radius by the measured ogive radius. The result is Rt/R.

    I'm sure there are other ways to skin this cat, but I've found this method to be (more or less) reliable and repeatable even if it is a little maddening.

    -Bryan
     
  10. Eaglet

    Eaglet Well-Known Member

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    I'm glad you answered that one. If my memory serves me well I did not read
    that in the book.

    It's a pretty awesome sneaky way of doing it. I like that! :)

    Thanks!
     
  11. Eaglet

    Eaglet Well-Known Member

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    Dear Folks,

    The OGW box was not calculating the varmint weight correctly.
    It was, of course, my bad. I also added to the info section seen
    when you right click on the underlined portion.

    just download from the link and replace the file.
    My thanks to the person who caught it and e-mailed me. I don't
    know his name. "I have a strong feeling is a 'He' ".

    Please excuse me for the inconvenience.

    http://pages.sbcglobal.net/jomoncada/Eaglet_Ballistic_Calcs/readme.zip

    Sincerely,

    Javier Moncada
     
  12. Chas1

    Chas1 Well-Known Member

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    Looks like you spent alot of time putting this together. Thank you for sharing.
     
  13. Eaglet

    Eaglet Well-Known Member

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    You're welcome!

    The Lord willing, I'll be adding more to it and make it even more useful.
     
  14. Eaglet

    Eaglet Well-Known Member

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    Re: (UPDATE) A small contribution to the shooting community

    A new tab page has been added. This concludes all of the book's formulas.
    A photo was also added for now to occupy empty space.

    Due to a small change in the .exe's name you'll have to delete the old one
    since it will not be replaced.

    Your input is appreciated.


    http://pages.sbcglobal.net/jomoncada/Eaglet_Ballistics/eaglet_ballistics.zip
     
    Last edited: May 11, 2010