i think you can learn a lot from smk air rifles they are cheep so if you mess up not the end of the world and you can normaly find parts s/h ,they are not
great out the box but with a bit of work can be very good xs20 hw95 clone think its b40 tx200 clone and the 78 and 79 imo give a good place to start learning
how pcp s work most of the smk s could do with the trigger polished ,seals changed ,inside debured ,re-crown the barrel ,new spring ,guides or polish
and there is lots of helpful imformation on the uk chinese air gun forum but be care full you might get addicted
Thanks for all the replies.
I will buy the book 'air rifle and air pistol maintenance and repair' by q.cobham and start accumulating some decent tools. I only want to repair my own guns and may be help others. It's not for a trade, unless I was competent, in which case I'd get an RFD certificate.
Thanks again
Dave E
.22 Webley Vulcan; .177 BSA MS Hornet; .177 FX Cyclone; 4 x .177 Gamo Delta's; .177 Brocock Hunter thumbhole stock; .177 Brocock Hunter Sporter.