I have 2 hw95s a .177 and a .22.
The .22 is tuned by wonky donky and is fantastic,hardly no movement just a thud upon firing.
My .177 is used for experiments to make the shot cycle nice trying different springs etc.
At the moment it runs a factory piston machined down to 195g with an aussie green seal and vortek spring and guides with steelsockets machined down to fit in the factory silencer for a tad more weight.It shoots very nice at the moment using jsb exacts 4.52 die54s for 10.8fpe.I have also put the action into an hw98 stock.More range time reqd after lockdown later this year.
From what i gather,the key to using the .177 seems to be linked to what state of tune the internals run.If the jumpy cycle can be tamed the rifle is capable of stunning accuracy.