Ballistic Testing
V50 is a measurement, not a prediction. The spread across the six shots decides whether the number means anything.
— m/s
Mean of the six fair-fire velocities
A negative spread margin invalidates the determination — rerun the series rather than reporting the mean. A negative zone of mixed results means completes were recorded below partials, which is normal and simply reflects the probabilistic nature of the limit. Armour acceptance rests on the governing test standard and a qualified range, not on this arithmetic.
V50 Ballistic Limit from Fair-Fire Test Series — free, with the formula and a worked example, at Textile School.