Well, I've spent all afternoon buggering about with mine again! Tried every jsb variant i have, which is a lot, and the best accuracy was with the 7.9 but this was not all that I had hoped for. So onto the other brands, first up ftt, power dropped from 11 to 10.6 probably dueto how tight they were in the breech which caused bounce and made it twang like a good 'un. Accuracy was great though which was a bit heartening. Next up rws superfield, again great Accuracy power 10.7. I decided then to add 3 steel washers into the piston to hopefully counteract the bounce and kill the twang. This pushed the power up to 11.1with ftt and did mute the buzz but whilst still accurate not quite as good and ruined the accuracy with the superfield. It was doing 11.6 with FAP, so still legal. Now I have decided to try another spring which has about 50-60 mm preload. Can't chrono now as its gone dark but had a few shots to see how it shot. Big spring twang on a std hw guide which is a tightish fit so ill chrono tomorrow and see how i go. I may just go back to the set up that shot the superfield well, clean the barrel and give it a good try.