Abstract : A modification of the Naval Weapons Laboratory, Dahlgren, Va. 1219 cm (40 ft) drop test and the Naval Ordnance Test Station, China Lake 305 cm (10 ft) drop test is set up and has been evaluated at the Naval Ordnance Laboratory, White Oak. The purpose is to find a way of accepting new explosives for fleet use without the necessity of making very difficult and expensive loadings for larger scale tests. A 45.4 Kg (100 lb) weight, upon being dropped, drives a 19 mm (3/4 in.) diameter stud into a cased explosive charge. All the energy of the falling weight is transmitted to the charge by the stud. The minimum height of drop which causes explosive action is an indication of the sensitivity of the charge. Results to date have ordered explosives in the same sequence as the Bruceton type impact machine.