[Blackmail]

I have a 120m/s spring for an AEG and it generate 0.75j (I have a 22mm of airbrake in my Striker AS-02): if I'll take a 120 m/s spring for a VSR it will generate much energy? If yes how muchis the difference for you(techincally)?

The springs are made for different platforms and usually aren't cross-compatible. To answer you first question, no. A m150 aeg spring will almost always have a lower output than a m150 for a vsr10. The aeg has a less consistent airseal, and a lighter piston plus other variables.