Exbal help for long range newbi

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by TyIdaho, Oct 9, 2009.

  1. TyIdaho

    TyIdaho Member

    Messages:
    24
    Joined:
    Jan 7, 2009
    [FONT=&quot]I am new to long range shooting and these forums so please bear with me here. I have read through the sticky post about altitude vs. barometric pressure, but I still have questions.[/FONT]

    [FONT=&quot]My only source for pressure (for now) is calling our local airport and getting the AWOS broadcast, I believe this is corrected pressure but I am not sure. So far the pressure that AWOS gives is the same as internet weather reports for my area.[/FONT]


    [FONT=&quot]When using Exbal:
    [/FONT]


    1. [FONT=&quot]Should I enter the AWOS pressure and uncheck calculate std. Pressure?[/FONT]
    2. [FONT=&quot]How do I enter new atmospheric data in the “Trajectory Validation” screen for each shooting session?[/FONT]
    [FONT=&quot]Thanks for any help.

    Tom
    [/FONT]
    [FONT=&quot]
    [/FONT]
     
  2. jmason

    jmason Well-Known Member

    Messages:
    1,527
    Joined:
    Feb 6, 2008
    Tom-


    1. [FONT=&quot]Should I enter the AWOS pressure and uncheck calculate std. Pressure? No (however if this is incorrect someone will correct me shortly) I always used a kestrel( for on the spot pressure or "station pressure") and a gps for Alt. Only when you do it that way do you uncheck Calculate STD. pressure".
      [/FONT]
    2. [FONT=&quot]How do I enter new atmospheric data in the “Trajectory Validation” screen for each shooting session? You only validate your trajectory one time. When you do it will use the conditions you input in the field conditions that day for the validation function. You can then Calculate and chose to use the new trajectory info and exbal will adjust your muzzle velocity.
      [/FONT]
     

  3. Ridge Runner

    Ridge Runner Well-Known Member

    Messages:
    987
    Joined:
    Dec 13, 2002
    You need to have the bar pressure as close as you can get it. Bar pressure effectively changes your BC.
    I always enter station pressure where I'm at. I use a casio sea pathfinder watch which is calibrated regularly. once you have your station pressure, alt. is a moot point, I always leave it on zero.
    This method works for me.
    RR
     
  4. TyIdaho

    TyIdaho Member

    Messages:
    24
    Joined:
    Jan 7, 2009
    Thank you guys for the feedback.

    jmason, if you only validate once why are there 5 data entry windows in the validation menu?

    So far I have four different ranges to enter validation results for, should I put them in all at once or one at a time? If I enter the data all at once the atmospheric conditions will not be correct for three of them.

    Maybe I am really missing the boat here?
     
  5. jmason

    jmason Well-Known Member

    Messages:
    1,527
    Joined:
    Feb 6, 2008
    Those five spots are for up to 5 different distances. You don't have to use them all but I'd use at least 3 and you do need to shoot all of them in the same conditions/day for it to be accurate. So go out and shoot (for exmaple 400, 500, and 600) at least 3 ranges with your current conditions in exbal and then use the trajectory validation feature. BTW have you already saved your sight in conditions? if you haven't you'll need to do that first.