Its very true about the RK-03 internals...
Upgraded na yung gun ko and expecting na aabot nga 470fps (at least kung ma settle 450fps

) pero during chrono tumatak lang 440fps. same as komrad taonggubats problem.
Second is yung hop-up rubber... 440fps down to 360 fps

hehehe. pero at least nakakatulong itong thread na to. update ko nalang after the major make-over