can i just add...
when you d get a tighter spring.... using c02
you shouldn't relly push your fps up to summut like 290..
espechily in hot weather
c02 pressure changes dramaticly depending on the weather.
on a hot day; if you push it up to 290.. you will find l8er on
when being chronoed by a marshal just b4 a game..
your fps will go to something like 340!
on a cold day you are probably safe to put it at 290fps
but w8 a bit untill your bottle warms up after re-filling