Older TC percussion lock no half-cock

[Sparkitoff]

I've recently gotten a friend in to black powder shooting and hunting. He was gifted an older TC Hawken 50 caliber today. It is in nice condition overall. The lock does not stay in half-cock. It will full cock and it will set with the set trigger and fire with the front, or just fire with the front. What do I look for to address the half-cock?

 

[Sparkitoff]

I've been able to answer my own question. There's a little pointy piece that pivots. I think its the fly. It was sezied up and no rotating fully. So it blocked the bar from engaging the half-cock notch. I used some penetrating oil and worked the part for a while. It began to move freely and now directs the bar into the half-cock notch, and into the full cock notch when the hammer is all the way back.

 

[necchi]

Yup, ya gotta lube that lock. That oil in there get's gummy, gotta fresh it up,,
Those T/C bridle screws need to be really tight too.
If they're a tiny bit loose, that fly will tip out a fraction and jam the hammer just short of contact with the cap.
Most folks start wondering why they get so many mis-fires,, it comes that close before it jamms.