Best Spin Drift online calculator?

Discussion in 'Long Range Hunting & Shooting' started by Litehiker, Dec 4, 2019.


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  1. Litehiker

    Litehiker Well-Known Member

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    I realize I can add "purt-near" spin drift info to my rifle's taped on drop table but I need something that will give me exact drift to 1,100 yards for both 6.5 CM and 6.5 PRC with MY muzzle velocities.

    I haven't yet purchased a Kestrel 5700 4DOF weather meter so I just need something online and free or cheap.

    Eric B.
     
  2. snox801

    snox801 Well-Known Member

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    I use the applied app it’s seemed to work good for fairly cheap
     
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  3. Tucker65

    Tucker65 Well-Known Member

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    Strelok works good
     
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  4. lancetkenyon

    lancetkenyon Well-Known Member

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    I use shooter. It allows me 1st round hits out to 1500 with spot on "wind" holds. This was with my 6CM pushing 105 Hybrid @ 3101fps. Just wished I would have thought about Coriolis too....
    These are through a spotter and zoomed in screenshots. But you get the point.

    1021 yards
    Screenshot_20190209-085847_Gallery.jpg
    1498 yards
    Screenshot_20190209-090435_Gallery.jpg
     
    Last edited: Dec 4, 2019
    Mram10us, Bob Wright, mwkelso and 5 others like this.
  5. Litehiker

    Litehiker Well-Known Member

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    Gents, I'm looking at those ballistic engines now. Thanks for the answers. Another "science project".

    Lance, Those are both fairly near center and at 1,500 yards that's just excellent.

    Eric B.
     
  6. lancetkenyon

    lancetkenyon Well-Known Member

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    Funny story. I went out with a bunch of guys I talk to, but had never met. They have a steel course set up, and had asked me to go shoot with them. Possibly (I have no clue) to see if I was BSing them about shooting. We got there, and they said, "You go first". So I unpacked all my stuff and I think they were a little apprehensive. Only 1 guy had brought a pair of 10s, but not tripods, no spotter, no rangefinders....
    So, I set up my 15s and spotter on separate tripods, and got settled in. They asked if they could use them. I said please do and call my shots for me. They pointed out various targets. I reranged them and pulled up Shooter, and started dialing.
    350....ding
    450....ding
    545....ding
    At this point, two guys said, "I am not even going to shoot now"
    580....ding
    700....ding
    820 was hidden by some grass, but I could see the chains. They said skip it. I said, "I got this".....ding
    1021......ding
    1498 had never even been shot at. I had never shot over 1250 with my 6CM at that time. But I felt pretty good.
    1498...........(didn't hear the ding), but the guy on my spotter said, "Are you effing KIDDING ME!". I said, "Did I hit it?" He said, "Come and look".....

    I went on to coach a guy who had never shot past 400 to hit the 1021 target, and within 8-12" of the 1498 target.
    He now texts me all the time. Just took an elk at 1108 yards, and has invited me to his Kansas farm next year to shoot some deer!
     
  7. trhall

    trhall Well-Known Member LRH Team Member

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    Fantastic shooting there buddy!!!!!
     
  8. George Dean

    George Dean Well-Known Member

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    I suggest that you contact these people for a custom Whiz wheel for each rifle (Ammo specific), about $50 ea. Or go all in and get the 5700 with Link and the windvane kit.

    Accuracy 1st, Inc.
    280 E. South St.
    Mooresville, IN 46158
    Phone: 317-584-3787
    E-mail: [email protected]
     
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  9. Canhunter35

    Canhunter35 Well-Known Member

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    Nothing like being a ringer lol
    I took a buddy, his expression when he put a second round hit on a plate with my gun at 1100 was priceless. Definitely got bit by the lr bug.

    4dof calculator offers g1/g7 curves also.
    If you’re wanting spin drift exact, you might as well calculate coriolos for 1000yd stuff
     
  10. Litehiker

    Litehiker Well-Known Member

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    Yep, coriolis effect needs an accurate compass heading to be accurate. That's why I'm going to get a Kestrel 5700 (4 DOF) and be done with it because it will also incorporate spin drift and modify TOF with altitude density. Just sold a 6.5 CM Browning X-Bolt and SWFA scope so I may spend on that Kestrel.

    Eric B.
     
  11. dfanonymous

    dfanonymous Well-Known Member

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    fast and free is just doing the math.
    1.25*(sg+ 1.2)*tof^1.83

    Solution comes out in inches so you’ll have to covert it to moa or mils. Whatever you’re using. Makes sure you use the tof for the atmosphere and corrected mv of when and where you are shooting, it’s not a do the day before thing.
     
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  12. Litehiker

    Litehiker Well-Known Member

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    df,
    My muzzle velocity should be about the same regardless of temperature (with temperature stable powder) or altitude density. It's many yards/meters beyond the muzzle where that stuff begins to be important the way I understand it.

    As i said above the Kestrel should handle all that for me IF my muzzle velocity averages are correct for various loads/bullets.
    I "need" that Kestrel. Th-th-that's my story and I'm sticking' to it when my wife asks me why I had to have it.
    I never paid attention to the compass bearing of our steel range but now I will record it just to see how it would determine coriolis effect. I know its "easterly" but by how much I dunno. That would make the targets by 1,000 yards drop lower during TOF and thus impacts be a bit higher.

    Eric B.
     
  13. dfanonymous

    dfanonymous Well-Known Member

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    You wouldn’t need to update density of air and temp (Mach) if it didn’t affect velocity in ballistic software now would you...

    This is a basic fact. You wanted to know a way to calculate it, this is how the kestrel calculates it, using this method. As I stated you want to make sure of these things as it effects time of flight (tof) (of your rifle and your cartridge) and time of flight which is varied in velocity is part of the literal equation.
     
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  14. jshepherd61

    jshepherd61 Well-Known Member

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    Buy the STRELOKPRO APP, I have about 20 apps to include AP ballistics and all the popular ones and through my testing in the past three years STRELOKPRO is the most consistent and scalable!