Hi Phil,
It's actually a lot easier than it sounds.
All you do is take out the adjusting screw behind the trigger, because it doesn't do anything anyway as it's not long enough.
And replace it with an old light socket screw.
The light socket screw will need cutting down, but screw it in first to figure out how much to take off.
First cock the pistol, then screw the screw in until it fires on it's own, then back the screw off by a quarter to half a turn.
Measure how much the screw sticks out and cut that off the end.
Give it a go, it made a big difference to mine.
Simon.
Theoben MFR CS800 .177/Burris Timberline, Theoben Evo .177/ Burris Timberline, BSA Supersport .25, Haenel XX, BSA Ultra .177/ Burris Timberline.