An update to this...

I've stripped the TX this morning. I've found two possible issues:

1. There was only one o-ring breech seal- isn't there supposed to be two fitted?

2. There's another o-ring which sits in a recess in front of the breech seals. It's wider so doesn't look the same. It looks chewed up/split.

I've added a link with images, arrow pointing to the chewed o-ring. Any advice appreciated.


https://ibb.co/album/5YbCFm