We analyze some physical peculiarities of a high-speed impact interaction between spherical die and plane barrier. Based on the kinematic relationships for initial stage of the interaction, we show that the intensity of loading of the die in the case of oblique impact is lower than that in the case of head-on impact. That can be one of the reasons of the higher penetrating power of the oblique impact, when the spaced barriers are used, and that was detected in some experiments. Based on this, formation of a more deep depression in the barrier from the side, from which the projectile moved, is explained. Analysis of this and other peculiarities of high-speed impact allows us to increase the impact resistance of covers by means of application of composite screens instead of plane plates.