The calculation of the V₅₀ value for a helmet requires a minimum of six shots to be fired at the helmet. The projectiles are fired on a test specimen with velocities of the predicted V₅₀ value. The three highest velocities of projectiles stopped by the test specimen and the three lowest velocities of the shots with partial penetration (Partial penetration is the situation, when the fragment manages to penetrate few layers of the helmet, however doesn't manage to fully pass through) are taken into account to calculate the real V₅₀ value of that helmet. A graphical representation of V₅₀ calculation is given in the diagram.