An armor plate for use in the ballistic protection of a structure against projectiles incoming from an expected threat direction, the plate having an outer face facing the threat direction and comprising a layer of first pellets made of ballistic material of a high density S1 and having a characteristic diameter DP, and second pellets which have a low density section with a central axis transverse to the outer face, along which the low density section at least partially extends, the low density section of the second pellets having a density S2 which is in the range 0≦S2