AirsoftTed

Unless I am totally talking out of my ar$e - you can expect up to 10% loss in fps in 3-6 months of use, maybe a little sooner depending on use. This is mainly the spring and some wear on seals etc... Please note I say up to about 10% and depend on quality of spring/seals/build etc... 15fps is say 4% so it might be worth leaving it pre-cocked over weekend.

You could end up replacing with m100 say = 328fps but come say Easter be down near 300 and paid for spring and/or fitting - might be worth a go and see if you can get her to tone down a little perhaps - my own aeg's have dropped a bit too and know even bolt snipers suffer spring drop

Sitting Duck, after adjusting hop to get under chrono, do you the re-adjust it so your shots aren't going sky high?