That makes so much sense, John. I remember Bigtoe saying years ago how "air hungry" the .177 is compared to .22. And that the. 25's appetite for air was equally insatiable. But allied to that lower back pressure you mention following pellet release due to the larger volume should make it very, very nice.
Still won't be homing one, though. I only shoot informal targets now and the rising costs and current family finances would make the .25 a luxury too far. Be lovely to get a ratting perm and try them, though!
Of my two 30mm 80s, both Venom tuned many years ago, my memory would indicate that the .22 was always much, much more pleasant to shoot. And the .177 more harsh. A bit puzzling considering the consensus on this thread and the ample volume. I did mention this to Steve some time ago when I collected the Vantage and Predator post refresh and he also seemed a little bemused, citing maybe a seal problem? I haven't shot either for years. Must pull them out of the cabinet (they have been back with me for 5 months as they lived at my dad's for years due to storage constraints), give them an airing, re-acquaint myself and decide any tactics.