A penetrator for a projectile with a tail assembly, wherein the penetrator includes at least one outer body that acts in a terminal ballistic manner for attacking an armored target, in particular a battle tank with reactive armor. The cross-section of the outer body perpendicular to a longitudinal axis of the outer body is a hollow cross-section. The hollow cross-section of the outer body has an area, and an area moment of inertia of the hollow cross-section is increased in comparison with a solid cross-section of at least equal area, so that the outer body has an increased bending stiffness on account of the increased area moment of inertia.