Of all the parts that look suspect it is the sear latch or retainer as it is sometimes referred to on some of the parts lists I have seen. It is the one that has the most distinct wear on it, not sure which side is the offending one, but the side facing the rear has the most about 1mm kind of ragged in that respect. I will remove the safety to see if tht is part of the problem, when messing with it if I played with that when it would not release the hammer it sometimes would.
I have been checking around on the internet for a new sear, Numrich is out, sent and inquiry to an site in Kentucky, not many obtions available. Can it be built up and rehardened??