Thanks, Francois and Ken. Those are good suggestions. I do have occasional access to a machine shop.I spent some time on it today. The Gamo spring just isn't suitable. It's two inches shorter than the original. Shimming it front or rear won't let it move the catch far enough back to get the sear to engage. (Perhaps some front, some rear will work.) Also thinking of just packing the spring with lithium grease to reduce the whang(!). It might be smarter to just leave it stock in case someone wants to buy it. I'll post up the results once it's reassembled and tested.Cheers,J~
Now that you've been into it, how much pre-load does the original spring have? Cutting coils and finishing spring ends isn't very hard, and if you do need an OEM spring to bring it back to original, it shouldn't be hard to find. if you have a couple inches of preload, you could probably take off about three coils, and still have an inch. Cut coils and finish end, and then add spring tar or Krytox. Don't use lithium grease. It isn't sticky enough and will fling off.