The use of different explosive reactive armor reactive cassettes is shown. Functioning rules of one- and two-layered reactive cassettes are presented. The paper demonstrates different kinds of tests with explosive reactive armour Wisniewski Adam (ERAWA) cassettes. There are some examples of the simulation of impact of different types armour piercing (AP) and high explosive anti-tank (HEAT) ammunition on these cassettes. Simulation was based on “free points” computer codes. The propagation of the detonative wave in the explosive (PBX 9404 and RDX) has been described with the use of the approximation of the so-called “detonative optics,” in which the front of the detonative wave is a surface of the strong discontinuity of the well-known shape (for the punctual initiation—the front is spherical) of the propagation speed, and the parameters of the medium on this surface are defined by the Chapman–Jouguet’s point. Scattering of products of detonation and their influence on the liner of the RPG-7M projectile are described with the use of equations of the hydrodynamics for the cylindrical symmetry. The results of the simulation process of the impact of AP ammunition of 7.62 mm, 12.7 mm, 14.5 mm, and 125 mm caliber, the type of armour piercing fin stabilized discarting sabot (APFSDS), are illustrated in figures. The changing of the following parameters on the axis, i.e., density, thickness, collapsing velocity, and pressure while penetrating of cassettes in time function, is presented. The next step to test the sensitivity of different types of explosive reactive cassettes containing different explosive layers placed on target, is the observation of their reaction to the impact of kinetic energy ammunition. Explosives contain different percentages of wax. The examples of reaction of the two-layered explosive of different thickness with different contents of wax after projectile impact are illustrated. Computer analysis of the parameters’ changes on the axis of the projectile’s penetration into explosive reactive cassettes, i.e., of density, thickness, pressure, impact velocity for different thicknesses of layers of these cassettes, and the projectile type and velocity 800 m/s and 1800 m/s, enables to know the initiation conditions of these cassettes’ explosive. The use of computer simulation makes possible to know the influence of the quantity of wax on the sensitivity of different thicknesses of explosives of one- and two-layered reactive cassettes.