190 Berger VLD BC brackets and drag

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Oliveralan, Sep 12, 2010.

  1. Oliveralan

    Oliveralan Well-Known Member

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    I am shooting the Berger 190vld at 2778fps and am looking to find what BCs to use for what velocity brackets. I am using Bulletflight Military on my iPhone and it has Bryan Litz's BC in it, however that's just one value..

    I tried Pming Bryan about this but his inbox is full.

    Does anyone have any Other BC data for the 190 .308 VLD?
     
  2. Oliveralan

    Oliveralan Well-Known Member

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    Bryan, maybe you can chime in here?
     

  3. BryanLitz

    BryanLitz <b>Official LRH Sponsor</b>

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    The average G7 BC for that bullet is .291. It changes so little that you can use that average value for all speeds and it will predict a very accurate trajectory.

    Just for fun, if you want to enter the multiple BC, it would be:
    G7 BC =
    .297 for 3000 fps and up
    .296 for 3000 fps to 2500 fps
    .291 for 2500 fps to 2000 fps
    .287 for 2000 fps to 1500 fps
    .287 for 1500 fps and below

    I'm interested in the difference in the trajectory predicted by a single G7 BC of .291 compared to the trajectory predicted by the above 'bracketed' G7 BC. If you could run that comparison and report the results here I think it would be educational for other readers.

    Thank you,
    -Bryan
     
  4. Oliveralan

    Oliveralan Well-Known Member

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    Thanks Bryan,

    just ran the numbers.

    Bracketed BC:
    600yards--70.7" drop--22.5" drift (10mph xwind)
    1000yards--294.1" drop--72.2" drift (10mph xwind)

    Single G7 .291 BC:
    600yards--71" drop--22.7" drift (10mph xwind)
    1000yards--295" drop--72.5" drift (10mph xwind)

    This was using my standard atmospheric data and a muzzle velocity of 2778fps.

    Granted there is no huge difference, however being extra precise I'd you have the ability doesn't hurt. This whole LR game is all about controlling variables.

    Thanks for the quick reply Bryan!