A 3D finite element model has been developed for studying the ballistic behaviour of bi-layer ceramic-metal target plates under the impact loads induced by the projectiles of different diameter to length ratios. The bi-layer target constituted of alumina 95, as front layer, backed by aluminium alloy 2024-T3 layer, has been impacted by steel 4340 blunt and ogival nosed projectiles of diameter to length ratios, 0.5 and 1.1. The constitutive behaviour of ceramic was modelled using the Johnson-Holmquist (JH-2) constitutive model while that of the metallic backing and the projectile using the Johnson-Cook (JC) material model. The range of incident velocity of the projectile was considered between 800-1000 m/s. The residual projectile velocity, damage induced in the target as well as the projectile, and the ballistic limit velocity (BLV) have been obtained for the different diameter to length ratios (of projectile).