I believe you'll either have to put up with the twang which is unlikely to reduce with use, or do a simple strip.
Take all safety precautions. BE SAFE.
A good spring guide is well worth while. Ensure the spring is intact and is a decent fit in the chamber.
Ensure spring ends are decently finished and add nylon washers at each end.
Ensure the piston head is in good condition and makes a good seal.
Ensure everything is nice and clean, especially the piston head and chamber right through to the transfer port.
Lubricate with a heavy grease - chain grease is quite good but Maccari Tar is also very good.
Ensure no lubricant is put ahead of the piston and don't swamp, just ensure good coverage.
The members' area describes strips on springers of various types. The advice is sound throughout and would apply to your springer.
While you have it stripped, clean the trigger block, remove any burrs and lubricate VERY lightly with a very light mineral oil.
Let us know what you do and how you've done it - better still, produce an article to share with other members.
Good luck. DaveL