Kodiak,
I figured you'd have gotten an answer before now. As much as I love my Contender, nothing serious has ever gone wrong with it in the 23 years I've had it, so I have never done more than disassemble it for cleaning. Which is a nice way of saying I don't have a clue to your problem. My guesses would not be useful, I'd have to have a working and nonworking example side by side to measure and compare. I love my .30 Herrett barrel and it works perfectly, so I'm not much help.
First I would ask next door at CB in the Single Shot Guns section. If no luck there, then I would call the factory 603 330-5659 and talk to a smith (not a CS rep, explain nicely that you need to speak with a smith), and if that didn't work then I'd go to Mike Bellam's(sp?) site. Thinking about it, the lack of real problems with any of my T/C products in the last 40 years probably tends to skew my attitude towards them a bit in the positive direction, you think? When I worked on guns for my living, any problems with T/C's got sent or brought down to the factory for service and were dealt with quickly and usually without charge. (When you get it up and running, I can give you a list of various moulds not to bother trying for your .30 Herrett, and a good list of bullets you might have some luck with.)