Parts can be sourced easily enough And as will all things , only change of you are compitent . The power difference between the .22 ( as it is set now ) and the .177 ( as it will be ) will need addressing straight away . Only to be done by someone who is well versed in these things .
These calibre change questions do come up quite often , i must admit , if it were me , i would probably just get another rifle , more expensive yes , but alot less hassle , and you have more to show for your actions .