• Winner! Quick Shot Challenge: What’s the dumbest shooting myth you’ve heard?

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  1. T

    JBM Ballistics question, FNG question.

    Awesome thanks! Im wrapping my head around this. Im starting to get it. Fred, My example , which Brad just described was a constant Density altitude of 5000 ft. In AZ I might find this in the lower deserts at 105 degree temps or in higher, cooler country .Same DA, two totally different...
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    JBM Ballistics question, FNG question.

    Thanks Fred!
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    JBM Ballistics question, FNG question.

    Yes. I too appreciate JBM. This one little issue is confusing me and apparently Im not the only one. Brad, Could you maybe elaborate on how higher temps increase the drag on the bullet via speed of sound changes? Maybe another highly experience shooter can chime in? Is it that with higher...
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    JBM Ballistics question, FNG question.

    When I use the this guys http://www.arcanamavens.com/LBSFiles/Shooting/Downloads/DA/ , I get different outputs than what it shows on his webpage. Has the software changed since these where made??? I still don't understand why, higher temps=more dope/drop on JBM ???!!!!! I've searched...
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    JBM Ballistics question, FNG question.

    Part of what confused was this page Making Ballistic Cards Using Density Altitude shows a DA card with two temps. The card shows lower drop and mil corrections at the higher temp with an equal DA.
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    JBM Ballistics question, FNG question.

    Should I just leave my zero temp and current temp the same and a mild 60 degrees?
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    JBM Ballistics question, FNG question.

    I miss printed me Ballistic AE output has has been corrected
  8. T

    JBM Ballistics question, FNG question.

    I want to clarify with a couple of examples. Lets use Arizona. I could find myself at higher elevations in the colder months with a DA of 5000ft( physical altitude of 6000ft with temps in the 20s). I may also find myself in the summer months in the western part of the state with DA of 5000 (...
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    JBM Ballistics question, FNG question.

    So awesome to hear from the creator. I love this forum! I guess was ,and still kinda failing to understand the effect of the Mach range and consequentially the effects of Mach with drag on the bullet. I totally get what your saying about the density altitude and temps not changing . I was...
  10. T

    JBM Ballistics question, FNG question.

    True
  11. T

    JBM Ballistics question, FNG question.

    I think you can, but Im not sure how yet...
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    JBM Ballistics question, FNG question.

    Making Ballistic Cards Using Density Altitude
  13. T

    JBM Ballistics question, FNG question.

    and this Barometric Pressure and Ballistic Software
  14. T

    JBM Ballistics question, FNG question.

    Read this - Manual Calculation of Density Altitude
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    JBM Ballistics question, FNG question.

    Station pressure is uncorrected pressure at your current location. Weather forecasts will give you corrected pressure for the altitude which is not station pressure. Density altitude is a combination of station pressure , temperature and to a lesser degree humidity.
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    JBM Ballistics question, FNG question.

    Temperature A temperature used to calculate a muzzle velocity for output. This input is also used to calculate the speed of sound to find the value of the drag function. This input is not used to calculate density. This came from JBM and is saying what you you all are saying. I get it, but how...
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    JBM Ballistics question, FNG question.

    So, when Im done. I may have several sets of DA cards ranging from -2000 to 10000. I will essentially have three sets of -2000 to 10000. A set of 20 degree, a set of 60 degree , and a set of 100 degree?
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    JBM Ballistics question, FNG question.

    Thanks for the help so far. So in the Trajectory Ucard and put all input the same for 168 SMK's @ 9000 foot elevation. The temp column to the left of the altitude column i put 30 degrees and the output at 800 yards was 7.6 mils 218.4 inches ( 2500 fps from 16inch) When I changed the 30 degress...
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    JBM Ballistics question, FNG question.

    I have been playing around with JBM a lot. I'm getting my dope cards figured out and making Density Altitude cards. Do most shooters make a DA dope card for each DA with increments of 1000 feet with "U cards"? If so ,what temp do you choose? Or make a " spread of DA's with a few temps, using...
  20. T

    NEW from XLR Industries **ELEMENT CHASSIS**

    Bom, how tall are you? I may take that stock.
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