Steel targets were shot by shaped charges. Instead of using conventional copper liners, in this test series liners made of aluminium and magnesium were used. The jet velocities ranged from 5 to 7 mm/μs. Behind the steel target a large Behind Armor Blast (BAB) - effect occurred. The measurement of this BAB was carried out by pressure and temperature probes located at different positions. Another measured parameter was the hole size in a thin aluminium witness plate mounted 1 meter behind the steel target. For a better understanding of the physical phenomena responsible for this strong BAB effect, hypervelocity impact tests with conventional spherical projectiles were carried out. These tests were conducted on a two-stage light gas gun using Al and Mg projectiles at the same impact velocity as in the shaped charge tests. The target consisted of a thin steel plate, followed by a thin aluminium witness plate. The first tests showed comparable BAB effects. The experimental test set-up, results and interpretation of the results are reported.