S200 calibre change

[Falconhoof]

I'll start with the normal "I'm gonna sound stupid here" comment but....
If I wanted to change a S200 from .22 to .177 would it simply be a case of changing the barrel, pellet loader and adjusting the power. Which in turn leads to the question what would be the best way to turn the power down? My rifle already has a slot made in the screw behind the hammer spring, could I just turn that to lower the pressure or is it more complicated than that?

[Roger5]

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