G&G sr25 low fps after upgrading

[Stubby12345]

Hi folks,

Well after upgrading ? my rifle the fps has went from 360 ish to 280 fps 😳. I'm running a guarder sp150 Spring, 11.1v lipo, upgraded shs piston, cylinder and Spring guide and an shs high torque motor. My hop up Prometheus bucking is good and there's no air leaks from there and the cylinder compression was spot on as it wasn't going anywhere when I put my thumb over the nozzle to check. I'm at a loss as to what could be the problem, if anyone can give me any pointers then it would be greatly appreciated.

Thanks.