A one-way explosive transfer assembly embodying a body formed with an interior chamber containing an explosive shock transfer body formed with shock wave attenuating passage means shaped to transfer heat and to control the explosive shock when traveling in one direction toward an explosive train and to check explosive shock if generated to travel in an opposite direction. The assembly includes an input shielded mild detonating cord means for conveying the triggering impulse to the explosive train and for transferring the effect of the explosive train to an output shielded mild detonating cord.