Abstract: The present paper analyzes the possible modes of shearplugging and adiabatic shear plugging in the perforation of metal platesstruck by a blunt rigid projectile. The modified ballistic limit andresidual velocity with adiabatic shear plugging are further formulated.Further experimental analyses are conducted on the perforations of Weldox Esteel plates, in order to discuss the effects of plate thickness andmaterial strength/hardness on the terminal ballistic performance. Moreexperimental evidences confirm the jump of residual velocity at ballisticlimit induced by the structural response of plate. With increasing thethickness of plate and the material strength, failure modes of plate maytransform from shear plugging to adiabatic shear plugging.