The paper presents the results of experimental studies of fragmentation of 6.35 mm spherical aluminum projectile impacting a thin continuous aluminum plates or a steel mesh bumpers at velocities of 6 … 7 km/s. The acceleration of the projectile was achieved by a two stage light gas gun. The impact took place under vacuum condition. We used continuous and mesh bumpers are of lower and higher areal density. In each pair of bumpers of different types the areal densities were similar. For the registration of after-impact fragment cloud we used thick aluminum witness-plates situated at some distance from targets normally to the shot-line. The post-mortem examination of the morphological features of the witness-plates allowed the comparative description of the fragment cloud generated at the impact. The digital processing of the pictures of the witness-plates damages provided estimate of the volumes of craters and the sizes of deeply eroded areas. The impact on the continuous bumper of the lower areal density produced the damages in the forms of chains of small craters. Peripheral ends of some chains were split like a fork – the morphological feature of the distribution of material in the ejecta cone generated at the impact of an aluminum projectile on a thin aluminum plate. On the other hand, the experiment with mesh bumper of the similar areal density produced thread like thin craters in the form of closed contours – never observed earlier effect. The mesh with higher weight showed the highest degree of the projectile fragmentation producing the number of small fragments several times higher the in the experiments with other bumpers of lower or similar weights. The integral distribution of witness-plate crater volumes was derived for all undertaken experiments. The data analysis was performed in the frames of Weibull distribution and the comparative analysis was performed among bumpers of lower and higher weights. The distribution of kinetic energy among the fragments in the after-impact cloud was derived.