Ballistic FTE & KAC Bullet Flight Question

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by jonthomps, Sep 27, 2009.

  1. jonthomps

    jonthomps Well-Known Member

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    I have both apps for the iPod Touch and there seems to be a discrepancy between the two ballistic algorithms each program runs. I can enter the exact same data in both applications but they show different energies, bullet flight paths, mil come-up's, etc. Could someone with (obviously) a greater mind than mine please explain this?

    Thanks,

    Jon
     
  2. BryanLitz

    BryanLitz <b>Official LRH Sponsor</b>

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    Jon,

    I worked with Robert Silvers (developer of the KAC Bullet Flight program) on his app. I don't have the program, or any iThingys to run it, but my understanding is that he verified his program using JBM which is a correctly written solution.

    Having never seen the FTE program, I can't comment on the difference(s), but I can tell you that whichever one better matches JBM is the more accurate program.

    Take care,
    -Bryan
     

  3. jonthomps

    jonthomps Well-Known Member

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    Hi Bryan,

    Thanks for the information. After reviewing both applications and comparing them against JBM's ballistic calculator the KAC software is the closest match. I'll stick with that one. Thanks again.

    Jon
     
  4. nfhjr62

    nfhjr62 Well-Known Member

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    Have Bullet Flight on my iphone and received this month two updates, the first don't rember but think was fixing some bugs and the one today was a fix for apps in meters
     
  5. jonthomps

    jonthomps Well-Known Member

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    Ok, here are my findings and it's very interesting!

    Below is a list of the data set constants. I set the same parameters for all three ballistics programs.

    Manufacturer: Lapua
    Description: Scenar (CD)
    Caliber: 0.338
    Weight: 300.0 gr
    Zero: 100 yd
    Muzzle Velocity: 2750.0 ft/s
    Sight Height: 2.25 in
    Line Of Sight Angle: 0.0 deg
    Cant Angle: 0.0 deg
    Wind Speed: 0.0 mph
    Target Speed: 0.0 mph
    Temperature: 59.0 °F
    Pressure: 29.92 in Hg
    Humidity: 45.0 %
    Altitude: 7600.0 ft

    Here are the results of the different software programs (at random distances) in no particular order of importance:

    Ballistic FTE:
    Drop (in.) Mils
    800 yd -142.23 4.9
    1300yd -473.89 10.1
    1800yd -1096.11 16.9

    KAC Bullet Flight:
    Drop (in.) Mils
    800yd -144.9 5.0
    1300yd -488.2 10.4
    1800yd -1144.9 17.7

    JBM Trajectory (Simplified)
    Drop (in.) Mils
    800yd -144.2 5.0
    1300yd -484.3 10.3
    1800yd -1131.2 17.5

    I hope this helps everyone make a much more informed decision!

    Jon
     
    Last edited: Sep 28, 2009
  6. jonthomps

    jonthomps Well-Known Member

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    nfhjr62,

    Thank you for the feedback, I'll keep an eye out for updates. I'm currently running Bullet Flight 3.0.0 and I feel this app (as documented from my previous post) is a much more accurate program.