Since the problem has been gradual & escalated when changing to muskets, you may need a lock assembly replacement.... maybe even a trigger assembly replacement. One of my recent purchases of T/C's did the same thing. I packed both off to T/C Inc for an inspection after I called them for advice. They agreed to inspect both parts. For the heck of it, I threw the hammer in the box too - before shipping it off. About 12 days later, a box arrived by UPS (Brown) with a brand new double-set trigger asembly, brand new hammer & brand new lock assembly. Works perfect now. I put it all on my 58-cal Renegade. I bought a GM barrel for it & now the rifle's like brand new.