Quote Originally Posted by Vernal View Post
I am using an AA seal,new from Chambers, but it is still much tighter than it seems should be. I had the same problem problem when I carried out your "simple tune " on my LGV,and you were kind enough, correctly, to point out then that the trouble was likely to be a tight seal. Resizing the seal, very time consuming, completely solved the problem, which is what caused me to start this thread in search of the best way to resize a seal. Nick G is kindly going to send me a run in seal which should confirm that the seal is the problem, or tell me to look elsewhere.
I'd completely forgotten about your LGV, but my gut feeling is still that your TX issue could well be air leakage.

True, AA seals do self size with use. With this thread in mind, I measured a brand new one on a piston today at 26.1mm diameter, against a worn but fully functional example at a little over 25.5mm. However, I have fitted brand new seals to TX200 pistons, and never had the muzzle energy issue you have experienced as a result, which is why I would be looking elsewhere.