I would check to see if the firing pin is broken. You can do this by removing the barrel. Take a pencil or something similar, use it to trip the interlock so you can cock the hammer without the barrel. The interlock is the bow-tie looking piece that the locking bolts are supposed to engage. Let the hammer down and look to see if there is indeed a firing pin peeping out of the firing pin block when the hammer is down. If the firing pin is broken, you'll need to send it out for repair, I don't think TC will send you the parts to fix it yourself anymore.
If the firing pin is not broken, then you probably have a problem with the locking bolts not fully engaging the interlock. Clean the frame around the interlock to make sure there's not any grime. Then give the locking lugs of the barrel you are using a good cleaning. Lightly oil everyting.
If this does not solve the problem, then you might have to stone the locking bolts a bit to make them fully engage. I'll bet that you might have the same problem with other barrels as well. I don't think you have a headspace issue, that will usually affect accuracy, not cause the gun to misfire completely.