Mach 1.5,
Spares/service kits can be had from :
http://www.customgunparts.co.uk/page7.html
I don't know if they can do the servicing work themselves, but it might be worth asking ?
It seems that this is perhaps not a rare occurrence :
http://www.targettalk.org/viewtopic.php?t=43912
Might be worth PM'ing Garvin here on 'BBS.
Benelli B76 (here on 'BBS) has rebuilt one (Post #5) :
http://www.airgunbbs.com/showthread....d-anschutz-250
Have fun & a good Sunday,
Best regards
Russ