Graham Henderson, one of the lovely chaps of notable fame from the springers-in-FT days, told me that many of the top shots wth sliding comp tube guns would boil the cylinder and piston & seal assembly to conform the seal to the cylinder without the use of abrasives etc.

.......But also that a sloppier fit would follow quicker than that of an unsized seal.

So you could try this method on the TX?

Maybe this could also be used on rifles that don't have a sliding comp tube by obtaining a short piece of tube with the correct ID and boiling the seal in that?

Personally I haven't ever felt the need to size, just allowing them to run-in naturally whilst keeping my eye on the power. But then I've not had one that I considered far too tight........

However, when I worked on the Mercury S a few months ago I did go for the Meteor 'O' ring for a far less tight fit.......

Mike, NickG has done some pretty awesome work with 'O' rings and 'X' rings. With the ease of strip-down on the TX I ponder whether it might be worth experimenting with home made carriers and the rings for sealing if you have plentiful playtime? Er.......I seem to remember him playing with a different material also recently?

Hope this provides a little more food for thought.