Power loss

[Murphy]

Did you not try everything before you took the coil off ?

[Geetee]

Thanks for replying guys,have ordered replacement spring

[TonyL]

Which version of the TX is it?

Did you measure the output before fitting the spring?

As the chaps have said, it may have been wise to try the rifle before reducing the spring down. But that's history now. If you have to wait a while for the new spring it might be worth adding some preload at the front end so as not to promote sear latching issues.

As CapitalBee has said, depending on how loose the piston seal fit is, this might be causing issues? If it is slightly loose at room temp and you are then shooting outdoors in these temps, the seal fit will be even looser as the seal contracts, reducing compression. If this was the case, you could try and re-chrono in a warm(er) setting.

What calibre and what pellets are you using?