In the paper the objectives of the Klotz-Club tests performed in Sweden are described. The main purpose of the tests is to give data on debris and framgment throw from detonations in ammunition storages in rock. The installation is described, and results from four of the tests are given. The Klotz-Club has its origin in 1966 when a group of people discussed the possibilities of reducing the blast effects from accidental explosions in underground ammunition magazins with a large closing device, a block (in German: Klotz). Theoretical and experimental studies were followed by a successful "full scale" proof test in 1973. The by that time four - participating countries decided to continue a fruitful cooperation within the fields of explosives safety. A number of efforts have been made within the frame of the Klotz-Club, cfr /1/.