Stress equivalence of solution hardening in FCC alloys was discovered by Basinski et al. in 1972. On the other hand, multicomponent solid-solution alloys have attracted much attention in the recent years. This study aims to revisit the stress equivalence of solution hardening and investigate relationships between flow stress and activation volume of FCC metals and low to medium entropy alloys for understanding rate-controlling deformation processes of multicomponent solid-solution alloys. The materials used were as follows: Cu, Ni, Cu-10, 30, 50, 60, 80mass.%Ni, CoCuNi, and CoCrCuNi with FCC structure. Tensile tests and strain-rate jump tests were carried out at 77 K and room temperature to evaluate strain-rate dependence of flow stress and activation volume of these metals and alloys. In the case of CoCuNi, a distinctive trend was found in the relationship between flow stress and activation volume. These experimental results were discussed in terms of thermally activated dislocation processes.