Abstract: Oblique penetration/perforation of metallic plates by rigid projectiles with slender bodies and sharp nose shapes is studied in this paper. The mechanism of ductile hole enlargement dominates in whole penetration procedure. In the present model, the directional change is assumed to take place near the front surface when the projectile heading into the target and being subjected to asymmetric resistance. It clearly shows that the perforation of metallic plate is dominated by four non-dimensional numbers, i.e., the impact function I, the geometry function of projectile N , the non-dimensional thickness of target and the impact obliquity . Explicit formulae are obtained to predict the penetration depth, ballistic limit, residual velocity and directional change for the oblique penetration/perforation of metallic plates. The proposed model is able to predict the critical occurrence of ricochet. The predicted results are verified by comparing with available and independent experimental data and existing models.