The Fps is at our limits here in Sweden for a DMR/Semi build (2,51 Joule). Maybe something is wrong but I doubt it, the bb goes straight, the FPS is correct and the BB is hopped properly. Maybe heavier bbs will make a large difference then. Are you sure you are reaching 80 meters with 400 fps and a straight hop curve?
Will try out some 0.43s when the weather has calmed down, stormy now so no point in that currently.
Btw
Tried a bunch of different valves (original, RA-Npas, Firefly, DP, and two more I cannot remember the name of) but they are mostly bogus, what makes the FPS difference is how thick the cap of the valve is and how stiff the valve spring is. You can make the original produce higher fps than the aftermarket ones using a dremel. The new G&P valves to look pretty good though, they have a short top and the same shape as the original preventing the valve rotating.