A shock testing apparatus for simulating pyrotechnic shocks comprises an elongate bar suspended for movement in a longitudinal direction, and a pendulum hammer suspended for impact with one end of the bar to excite it into longitudinal resonance. A mounting assembly at the opposite end of the bar allows test components to be mounted in three perpendicular x, y and z orientations relative to the bar. A reversible drive motor raises the hammer to a predetermined height under the control of a control assembly which switches off the motor to allow release of the hammer when the predetermined height is reached. Damping masses are clamped at pre-selected positions along the bar to produce a predetermined shock response spectrum on impact with the hammer.