The TX compression cylinder seal

[Phil Russell]

To recap: power peaked out and no matter what I did I could not increase it above about 750fps with JSB 8.4. It all pointed to a leaky compression cylinder seal. Removing the end nut/bolt defeated my attempts but maybe I did not use enough heat and should have used a more robust cylinder clamp. Much advice received on both counts from here ... thank you. But just out of devilment I wondered if it was possible to seal the end bolt from the outside. So ... JB weld applied in a thin ribbon around the hexagon bolt head and allowed to cure about 24h. Result ... good and consistent increase in power to where I was aiming, c. 780fps with no changes to my initial spring/ delrin top hat about 1cm deep (same as steel top hat) and no preload washers on the guide. Cocking is not too hard, firing cycle is nice with a pleasing 'thunk'. So far maybe 150 shots fired and no signs of the JB cracking / coming free.
Will it last? Time will tell. But if it fails I can remove it to reveal the bolt head flanges and start again.
Here's hoping.
Cheers, Phil

[NickG]

You have proved it was leaking , so now take it out pop a new o ring in and loctite it as well ( the o ring doesn't always seal on its own ) if you heat the end until the loctite smokes it will fly out, done a lot of these & never had a problem .

[LESS THAN FORTUITOUS KENNETH]

I had the same problem a couple of months since. Nick came up with the same solution he has given you. It worked a treat. I expect a lot of Tx's would benefit from this checking out while you have them stripped.