Funnily enough, I have in the past bought FWB sports cheaply because the piston seal had failed (and crumbled into dust almost). Sight wise, I now know what I need, due to a useful Pyramidair blog and the useful vintage air arms forum from Garvin. The trouble is, they cost almost what I paid for the whole rifle . I'm torn between a full on restoration, or a spruce up and maybe fitting a vintage Weaver scope I have put by.