An equation of state (EOSs) for the products of a high explosive (HE) requires calibration in order to determine the appropriate value of material-specific parameters. This calibration is normally done with respect to experimental data, and for HE EOSs, the cylinder test is generally used. A database of experimental cylinder test results has been compiled. In a cylinder test, a metallic cylinder (usually copper) filled with the HE of interest is detonated. The cylinder expansion is observed using a streak camera, and detonation velocity is determined using time-of-arrival pins. Optimization, through matching test conditions and results to an EOS form, either directly or indirectly, gives the EOS parameter set. The current database of tests will be presented, as will progress in using this database to calibrate the parameters of the Jones-Wilkins-Lee EOS form. ©2000 American Institute of Physics.