Just to clear something up; does the Mk2 TX and ProSport have 84mm or 96mm stroke? Or is it just the Mk2 TX that remained at 84mm piston stroke. I were told that post year 2000 all TX and PS went to 96mm stroke, if so what's the general consencus this makes to a .177 shot cycle set at 775fps 8.3gr? I mostly use a Mk2 PS that I've replaced the stock AA main spring with Vmach replacement mainspring guide set with Vmach parachute seal plus I've removed the steel top hat and that now feels quite snappy despite the assumed longer stroke. So with a highly stored energy mainspring such as the Vmach type, am I right in thinking that the increased action speed makes up for a longer piston stroke? Many thanks.