G1 vs G7

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by BuckSnort, Jun 7, 2011.

  1. BuckSnort

    BuckSnort Well-Known Member

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    Which are you guys using? I was just messing with my ballistics program and for my 270WSM with 130TSX @ 600 yards there is an elevation difference of 1.4MOA and with a full value 10mph wind there is a 1.6MOA difference..

    At 1000 yards there is 5.1MOA of elevation difference..
    Wondering if any of you have done any real world test's comparing the two drag models?

     
  2. cowboy

    cowboy Well-Known Member

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    I find the G7 to be much more accurate in real life after 500 yds. There isn't much difference that I have found in less than 500 yds. Still have to verify in the field but the G7 will get you a lot closer in my experience.

    The main problem in the G1 is that some of the bullet manufacturers are a little too lenient or optimistic with their stated BC's in my opinion.

    Go G7 and field verify and you will be good to go.
     

  3. J E Custom

    J E Custom Well-Known Member

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    Real world testing to me means actually firing at different distances. (100 yards to 1000yards)
    and comparing the results with calculated drop tables using the G1 model and the G7 model.

    Without exception the G7 model was closest to actual.

    If you use a spitzer flat base the Gi is close because it closely matches the G1 Model. But for the
    secant ogive boat tail bullets the G7 is the one to use.

    Just what I have found.

    J E CUSTOM
     
  4. rscott5028

    rscott5028 Well-Known Member

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    not to split hairs... But, both models were developed in the real world.

    Like JE points out, the best fit will depend on the type of bullet you use.

    If neither works for you, then you may not be inputing all the right data.
     
  5. Eaglet

    Eaglet Well-Known Member

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    It seems to me you may be doing something different. There should not be that much
    difference at 600 yards. What values are you using for G1 and G7?
     
  6. CRNA

    CRNA Well-Known Member

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    I use G7 for my ballistics calculator on my iPod and it is spot on.
     
  7. Eaglet

    Eaglet Well-Known Member

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    What vales are used for BC1 and BC7?
     
  8. BuckSnort

    BuckSnort Well-Known Member

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    I could very well be doing something wrong.. To be honest I am new at the long range game.. I am just running the numbers through my Shooter App with my phone.. The G1 mode shows a BC of .431 ... For the G7 mode all that shows is the selection for that mode, the BC numbers don't show.. Like you said, there sure seems to be a big difference between the two..
     
  9. Eaglet

    Eaglet Well-Known Member

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    As you can see below, up to 800 yards there's really no concern with vertical adjustment.

    trace1 = using G1
    trace2 = using G7

    BC for G7 was calculated by the program.

    G10G7.jpg
     
    Last edited: Jun 9, 2011
  10. BryanLitz

    BryanLitz <b>Official LRH Sponsor</b>

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    BuckSnort,

    The large difference you're seeing between the two suggests there is something wrong with the calculation; there should not be that much of a difference. I suspect the program is using a G1 BC when it's running in 'G7 mode', or vise versa.

    What bullet are you using? I'll try to re-create your results in Shooter and help sort it out if I can.

    -Bryan
     
  11. BuckSnort

    BuckSnort Well-Known Member

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    Thank you for you're time.. I'm gonna be shooting 130 TSX @ 3100 (hopefully) I actually have not loaded them yet but my rifle shoots the 140 TSX good but I only have a few left so I figured I'd switch to the 130's for the higher BC..