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#38 – Ballistic Programs

Ballistic Programs

01:20:07  | This episode is from Chapter 8 of Applied Ballistics for Long Range Shooting. Bryan and Mitch discuss the different types of ballistic solvers, what’s under the hood, and principles of effective use. In the old paradigm, shooters considered ballistics programs to only be capable of approximate solutions. In recent times, it’s generally accepted that solvers can provide extremely accurate fire solutions if driven with accurate inputs. This discussion takes you thru that paradigm shift and the important things to know to get the most accurate fire solutions from your ballistic solver.

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  • Kaleb Anderson says:

    Towards the end where you discuss truing, I went through Todd’s back in 2010/11 when I was active duty and we trued by changing MV and used DA as our input for data. Do you true MV or BC? Other instructors are saying BC is the wild card based on how accurate our chronos are now and BC can change based on other factors? Would you suggest using DA still or is it better to use the 3 independent factors for an AB based product. I believe the guys teaching Hornady 4DOF say to use the 3 independent readings and also to true BC instead of MV just curious what your thoughts are and why there is 2 different “schools of training” and what does the science say is the “right” way if there is?

    • Bryan Litz says:

      Very good questions!

      There are different reasons you may select to true different variables. In principle, you want to true the variable that you have the least confidence in.

      Speaking of the AB software, the bullet data in our library (BC’s and CDM’s) are all live fire measured with Doppler radar so the bullet data is a high confidence input. Back in 2010-11 BC was much more of a wildcard hence the dilemma you stated. These days bullet data is nailed down pretty good so for most users, MV input is a much greater variable and some users don’t even have access to a chrono in which case you’d obviously true on MV.

      Another principle to decide which variable to true (first) is to consider the effect of that variable. For example, MV is an initial condition which it’s effects are seen immediately in the trajectory. So it makes sense to true MV from muzzle to trans. Whereas BC (drag) has a cumulative effect, so it begins to impact trajectory further down range. This is why the AB software is set up to true MV first, then, if necessary (it’s often not), you can calibrate the DSF (drop scale factor) which cleans up any residual error beyond transonic.

      Hope this answers your questions,

  • Andres Bula says:

    So basically between a kestrel 2500 (barometric pressure) vs 2700 (stationary pressure), which one is more useful to get accurate solution at different altitudes?

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