As a traditional experimental approach, the cylinder test has been widely applied to evaluate the ability to accelerate metal, acquire the specific dynamic energy, and calibrate the equation of state of the detonation product for an explosive. In this article, based on the constant metal-density Gurney formula, a theoretical approach to predicting the expansion history of a metal cylinder shell driven by the detonation product of a multicomponent explosive under any explosive mixture ratio is proposed, providing that the corresponding theoretical density and the initial internal energy and the Jones-Wilkins-Lee parameters of each explosive component in the multicomponent explosive are known. Based on this predicted expansion history, the ability to accelerate metal, the specific dynamic energy, and the equation of state of a multicomponent explosive under any explosive mixture can all be acquired without an extra cylinder test for the multicomponent explosive itself. For verification, numerical results for the expansion histories of a copper cylinder driven by the detonation products of a PBX-C03 and a Comp-B multicomponent explosive were calculated and found to be in reasonably good agreement with previous cylinder test data.