Many years ago, I had a Relum Tornado. Right, confession over. To try and improve it, I tuned it following instructions from one of the Airgun magazines. This was early in 1985, and I suspect that the magazine was the sadly missed "Sporting Air Rifle". I dri-slided the air chamber and fitted a Meteor spring in place of the awful concentric ones, but this is the part I can't remember clearly, I seem to recall fitting a PTFE piston seal, how I did it or what rifle it was from completely escapes me. I'm trying to remember because I was talking to a chap the other day who still has one, and was interested in tuning it.
Does anyone remember the article? Or have any idea where the seal came from or how to fit it.

Bob