Why don't you get yours serviced and restored with new parts? That was a real cracking accurate Pro Sport you have there. You made me envious with the hunting experiences it gave you.
two reasons why not mate, 1) id have to replace the entire action, underleaver assembly and cylinder, and air arms wouldnt sell me an action on its own minus the stock and 2), ive knackered my left shoulder/upper arm with a repetitive strain injury that leaves me with no strength in my leading arm and fekks me up for work so springers are currently a no-no sadly. not to worry, im thoroughly enjoying a brand spanking new hw110 instead, and ive kept my diana mauser clone for when im able to use spring guns again. said diana has a gold SFS sticker on it now so you can imagine how good that gun is now!!
sure it wont be long til you have some equally enviable exploits with your PS mate, looking forwards to reading about them