Hi Folks!
I'm hoping I might be able to pick someones brains.....

I have just picked up one of the guns of my teenage dreams; a BSA Airsporter Stutzen
Its shooting fine, but having chrono'd it its pretty low; averaging about 320fps. I suspect it simply needs a good overhaul and a new spring, but I'm not familiar with Airsporters and so don't know if there is a specific spring for the various models. This is a .22 calibre one with the serial number GR00306. I've tried googling 'BSA Serial numbers' but haven't managed to find any online details for dating the rifles; just the motorcycles. (As an aside I do have a nice 1954 M33... but I digress!)

I'd be grateful if anyone could tell me roughly how old my new beastie is and if they have any recommendations for springs.
Thanks!!
Anne