Pro Carbine velocity problem

[FalconGuy016]

I just went paintballing today with my carbine and when I first chronoed (with a relativly cold tank) 240's. The ref told me keep it my tank will warm up. Then it did, up and past 300. And eventually to 350 all the way turned down. It didnt do this last time I played, and I checked my velocity adjuster screw and it seemed ok. Can anyone help?

[Spray Painter]

Did you stretch the main spring out. when i han mine i strtched the sping out and it was shooting at around 350. the ref was mad at me... and i had to screw in the velocity ajuster all the way