Of course the calculator is useful for initial setting - kind of like boresighting. But I have seen on numerous occasions the ballistic calculator giving the wrong dope, as much as 2MOA at 600 yards in one case (that’s 12 inches)with my 7mmRM and 162 SST's this past summer. I needed to drop my input velocity by 100 fps from what my chrono and calculator told me to get everything lined up precisely.
And assuming your shooting a properly zeroed rifle (a given i figured), 1-2 shots is all that is required to validate field bullet drop and suntension setting. But more shots are always better
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