The structural dynamic behaviour of cylindrical explosive chambers to internal blast loading produced by concentrated explosive charges is studied. Special attention is given to the formation and development of dynamic strain growth and the factors which affect it in the dynamic loading of explosive chambers. Theoretical treatment of the strain growth and strain growth factor is given for the first time. It is pointed out that the superposition and interaction of different modes of response with similar frequencies is regarded as the mechanism of strain growth and that the geometry of the chamber is the crucial aspect controlling the degree of strain growth. In the theoretical analysis, the shell equations which consider transverse shear and rotatory inertia are adopted. Two test vessels with length to diameter ratios of 1 and 2, respectively, are used in loading experiments with three different amounts of explosive charge. The experimental data and theoretical computations are compared and show very good agreement, confirming that the method proposed in this paper can be applied to estimate the strength of cylindrical explosive chambers subjected to internal dynamic loading.