This paper focuses on the mechanical behaviour of aluminium alloy 2024-T351 under impact loading. This study has been carried out combining experimental and numerical techniques. Firstly, experimental impact tests were conducted on plates of 4 mm of thickness covering impact velocities from 50 m/s to 200 m/s and varying the stress state through the projectile nose shape: conical, hemispherical and blunt. The mechanisms behind the perforation process were studied depending on the projectile configuration used by analyzing the associated failure modes and post-mortem deflection. Secondly, a numerical study of the mechanical behaviour of aluminium alloy 2024-T351 under impact loading was conducted. To this end, a three-dimensional model was developed in the finite element solver ABAQUS/Explicit. This model combines Lagrangian elements with Smoothed Particle Hydrodynamics (SPH) elements. A good correlation was obtained between numerical and experimental results in terms of residual and ballistic limit velocities.