high i have just renewed all the working parts inside my meteor mark 3 which i think is the same as yours , i put an ox spring in it and found that it was hard to pull the trigger, i contacted a shop called john knibbs TEL 01675481006 he deals in all the old and new bsa spares he advised me that the gun was not able to take the extra power put out by the ox spring without a lot of extra mods done, (it would blow it self to bit eventually) so i went with his advise and put a new standard spring back in it, which i have done today, and it has made all the difference to the trigger and the gun,
but as a long range target gun i have had meteors for 30 odd years and they aint long range target guns, up to about 35 yards yes ok, but over that forget it, but to renew all the parts inside your meteor which is a mark 3 by the way will cost you about £50 plus, depending on how far you want to go with it, so for long range you will have to find another gun for that, hope this helps
muzzy