AbstractAn equipment used for testing the response of watergel explosives to weak shocks is described. The main purpose of these tests was to investigate the shock‐initiating hazards when pumping watergel explosives of the non‐cap‐sensitive type. The explosive sample (weight ∼ 20 g) was confined in a steel cup and rapidly compressed by a steel piston. Tests were carried out with watergel explosives of both the cap‐sensitive and non‐cap‐sensitive types. In Bulkreomex (a pumpable watergel), a weak reaction was observed at a peak pressure of 1.7 kbar. As piston velocity increased, the reaction became more violent, and at a velocity above 20 m/s the reaction produced a sharp