AbstractExplosion times of PETN pressings and PETN/tetryl assemblies have been measured as a function of the length and density of the PETN donor charge and the density of the tetryl acceptor. A charge length of about 3.5 mm is necessary for the PETN explosion wave to reach steady‐state velocity for the densities studied. The initiation of the tetryl pellet is related to the detonation velocity (and presumably peak pressure) as well as the pressure‐distance profile generated in the PETN explosion wave. Higher‐density tetryl charges appear to be more sensitive than