If a shooter doesn't have access to an accurate chronograph, doesn't know the exact BC, etc, they can still use ballistic programs to predict their trajectories by applying ballistic truing. This is when a ballistic solution is
Some programs such as Shooter have a built in feature to automatically true the data that is required to match your real world drop.
If a scenario exists where all the inputs cannot possibly be known with a high degree of certainty (as is commonly the case in some scenarios), then using conditioned
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tweaked to match some real world data.