Welcome Doug, The 5 mm 34 is somewhat rare. Have you dated yours, The numbers to do so should be on the right side of the receiver iirc. Should read something like 1289. 12 meaning Dec and 89 for 1989. This will also help you figure out what version trigger you have. Depending on when it was made you may have a T01-T06 trigger.
Air rifle headquarters has tune kits here
http://www.airrifleheadquarters.com/...age/251488.htm and so does
Vortek
http://vortekproducts.com/ourstore/R...20Tuning%20Kit
Dave