The paper is reporting some comparisons between experimental and numerical results in terms of failure mode, failure time and ballistic properties of mild steel sheet. Several projectile shapes have been considered to take into account the stress triaxiality effect on the failure mode during impact, penetration and perforation. The initial and residual velocities as well as the failure time have been measured during the tests to estimate more physical quantities. It has to be noticed that the failure time was defined using a High Speed Camera (HSC). Thanks to it, the impact forces (average and maximum level), were analyzed using numerical simulations together with an analytical description coupled to experimental observations. The key point of the model is the consideration of a shape function to define the pulse loading during perforation.