I have had the same problem with my 308 barrel. I have 2 other barrels for the same frame with no problems. After much research and good advice, I have come to the following conclusions.
1. It is not the ammo
2. It is not the firing pin
3. It is not the frame per se ( although the headspace using this particular barrel is probably excessive.
4. It is most likely a combination of excessive head space and the barrel is cut too deep. (The barrel may do fine in another frame ...just not this one)
I called T/C and they tried to tell me it was because I was using a hammer extender, which is ridiculous, because the other 2 barrels would be affected also if that where the case.
I have sent the gun back to T/C today and they are going to perform some tests and fix the problem...or at least that's what they said.
In the meantime, after talking to MikeBellm, I have a couple of other tricks up my sleeve in case T/C strikes out.
1. I'm going to use higher (see-through) scope rings so that I won't need to use the hammer extender,.
2. I'm going to have MikeBellm do a trigger job and install a stiffer hammer spring.
3. I'm going to make sure that I only use the factory loads that work well.( I have tried 8 different loads and only 4 have misfired...the others do fine with very good accuracy.
I hope this helps answer your question...believe me, I've gone around and around on this same problem. Let me know if I can help more.
Blaine