I've got a small collection of post-war webley spring rifles, and have managed to get a few of them sorted out.

But one of the .22 Trackers seems more difficult than the others.

I have checked the tap alignment, and it seems fine. Not much leakage either.
Tried several seals, bot the teflon type, and fitted Gamo/AA-type seals.
All possible brands of new and vintage pellets.
Several different springs.
More piston weight.
Differing preload on different springs.
Little lube, much lube, in between etc, several types of greases.
Polished the compression tube and transfer port, radiused the port entry slightly.

I had a combination with Maccaris spring, a fitted gamo seal, max preload and a large piston weight that was pushing superdomes at about 570fps, but It did recoil a bit too much. Other Trackers have been much easier to work with, giving similar results with the same spring with less spacing, and less piston weight and the original seal. I dont waht to push the gun too hard!

So, I'm hoping some of you guys might have an idea of something I have not tried... anyone?