Gamo cf20f adjustment trigger screw size

Hi everyone, 

I have a gamo Cf20f and I wanted to change the screw that is used to adjust the trigger. It is 2.2/2.3mm of diameter and 6.5mm length without the head. I use a torx 8 (T8) to unscrew it. Is it an M2 or an M2.5? Could you please link me a set of screw of the correct metric size, 8 or 10mm long to change with the original one? . Do someone has done this modification? I will put some photo down here
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