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Thread: An APP to determine drop based on existing data

  1. #1
    Site Supporter CCT125US's Avatar
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    An APP to determine drop based on existing data

    Having trouble picking up FPS with chrono.

    Sun and shadow issues weren't helping me out today.

    Is there an app to determine holdovers if I know the drop at various distances?

    For instance, 100yd zero, and true holdovers at 200, 300, 400, and 500 yards so far.

    Am I able to plug these numbers in to determine midpoint and beyond?

    Looking for an Android campatable solution.
    SWYNTS
    Just because it "feels good", doesn't mean it's best.

  2. #2
    Strelok can help you do this

  3. #3
    Site Supporter entropy's Avatar
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    Apr 2012
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    Midwest. Far Upper Midwest whever I get the chance
    Google JBM Ballistics. I also believe Ballistic has an android app.

    For your chrono issue, try painting the bullets with a black Sharpie marker and/or taking a couple sheets of typing paper and taping them across the diffusers.
    Working diligently to enlarge my group size.

  4. #4
    I am confused. If you have actual measured "drop" at those ranges, what is lacking? Are you talking about something to show holdover at, say, 367 yards given 300 and 400?

    I would undertake to back calculate in JBM until everything matched up.
    Code Name: JET STREAM

  5. #5
    Site Supporter SecondsCount's Avatar
    Join Date
    Feb 2011
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    Utah, USA
    How far are you shooting and what is the target size? There are a ton of variables besides velocity that start to become more critical the further out that you shoot. Atmospherics- especially wind, ammo temperature, ammo accuracy, and even bullet BC variations.

    Quote Originally Posted by littlejerry View Post
    Strelok can help you do this
    I like Strelok, there is a free simplified version and a Pro version which does even more. There is a "truing" function in the Pro version that will allow you to shoot at a couple different distances and enter data based on what you see on target. The app will then extrapolate the drops from there.

    It is kind of like a 25/200 yard zero. If you zero at 25 yards, your chances of hitting at 200 should theoretically be good but you never know unless you actually shoot that far to be sure the velocity, BC, height over bore, etc all line up.
    -Seconds Count. Misses Don't-

  6. #6
    If you already have solid recorded dope for multiple distances, setting up a ballistic calculator to give you viable data for different environmental conditions and ranges is pretty straightforward.


    Look up the BC (G1 or G7) of the projectile you're shooting. input that into your calculator with a "guess" for your muzzle velocity.
    Make sure you input the environmentals (temp and pressure) into the calculator that were present when you collected your actual dope.
    At this point adjust your velocity to get your 500 or 600yd dope to match. Then you can make small adjustments to your bc to get the the further drops to match up.

    Hope this helps

    ETA: I've had pretty good luck with shooter and applied ballistics on my android devices. There's certain things about both programs that irritate me, but they work well.
    Last edited by pyrotechnic; 03-31-2021 at 03:31 AM.

  7. #7
    THE THIRST MUTILATOR Nephrology's Avatar
    Join Date
    Sep 2011
    Location
    West
    Quote Originally Posted by CCT125US View Post
    Having trouble picking up FPS with chrono.

    Sun and shadow issues weren't helping me out today.

    Is there an app to determine holdovers if I know the drop at various distances?

    For instance, 100yd zero, and true holdovers at 200, 300, 400, and 500 yards so far.

    Am I able to plug these numbers in to determine midpoint and beyond?

    Looking for an Android campatable solution.
    Strelok Pro is the best $18 I've ever spent.

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