The penetration depth of rigid projectiles is investigated using the modified spherical cavity expansion theory and the HJC model for the concrete targets, in wluch the model parameters used in the Molw-Coulomb Tresca-limit yield criterion are obtained by the triaxial compression tests. By comparing the cavity expansion pressures of the concrete samples with two different types of aggregate, the influence of the aggregate hardness on the penetration processes is discussed. With the analysis of the tractions acted on the projectile nose, the influences of the projectile and target material properties as well as the projectile struchme on the transition impact velocity are also discussed. By comparing the theoretical results with the experimental data, two penetration mechausms are demonstrated for the ogive-nose projectile penetration into concrete with the striking velocities np to 2.Okm/s