Combined effects of dynamically charged helium and neutron damage on density change, void distribution, and microstructural evolution of V and V-4Cr-4Ti alloys have been determined after irradiation to 18–31 dpa at 425–600°C in the Dynamic Helium Charging Experiment (DHCE). The results were compared with those from a non-DHCE in which helium generation was negligible. For V-4Cr-4Ti specimens irradiated to ≈18–31 dpa at 425, 500, or 600°C with a helium generation rate of 0.4–4.2 appm helium/dpa, only limited number of helium bubbles were observed either at some Ti(O,N,C) precipitate interfaces, in localized regions of grains, or near grain boundaries. Neither extensive coalescences of helium bubbles on grain boundaries, typical of some alloys irradiated in tritium-trick experiments, nor dense helium bubbles within grains, typical of unalloyed V or alloys not containing Ti, were observed. Under the conditions of DHCE, most of dynamically produced helium atoms seem to be trapped by irradiation-induced defects and defect clusters within grains or fine Ti5Si3 precipitates, which prevents significant bubble nucleation or growth. Density changes measured on specimens irradiated in DHCE or non-DHCE were low (<0.5%) for all the irradiation conditions investigated (425–600°C, 18–34 dpa, and <4.2 appm He/dpa).