This piston cup is designed to work with stock SSG10 cylinders, it has a slightly smaller diameter to give optimal results in terms of power can consistency.
For reference, a Rapax Lightpull Blue 2J+ spring is giving 2.2-2.3~ joule in an stock SSG.
Thumb block seal.
Normal Joule Output
We recommend buying some spring guide spacers to adjust the joule a bit.
