I noticed that the O ring on my breech plug had a tear,in the surface of it. I've been told that T/C has replacements for them. But not wanting to wait,I took the damaged O ring with me today to the auto parts store (NAPA) The salesman took it went into the back of the store,and came back with a box of O rings,and said how many do you want,I said 4. He then measured it on the size chart of the box and handed me four new ones,plus the old one. He said you owe me a dollar. I wish I had looked at the box diagram closer,so I would have a Part# or size. But if yours is worn,just go to the auto parts store and hand them your old one,and at $0.25 a peice it's hard to beat. Ron The damaged O Ring is on the Left side of the picture.