Figs.10 presents the experimental comparisons of the measured stress-strain hysteresis responses for the 1st cycle between SSFS and MTP specimens for FV566 steel at 600 °C subjected to saw-tooth loading. The accuracy of the 1st hysteresis loop under high temperature LCF test is particularly important as it can be used to determine the elastic and kinematic parameters, e.g.,E , , , , for Chaboche unified visco-plastic model in this paper1-3. As can be seen from Fig.10 (left), the reversible hysteresis responses from MTP specimens using the determined scaling factors show an excellent agreement comparing with the SSFS testing results under the equivalent testing conditions, in particularly for the MTP-3 with the weakest geometry constraint effect. In addition, the hysteresis loops of MTP specimens exhibit obvious identical dynamic strain hardening as SSFS testing. To enable a direct comparison of temporal stress evolution behavior between SSFS and MTP specimens, the stress data versus normalized time are plotted in Fig.10 (right), again, showing a very good agreement. Maximum tensile and minimum compressive stresses in the three MTP specimens are nearly identical to those from the SSFS testing for the first cycle, especially for the MTP-3 specimen.