I've been fighting with that revolver for a long time. Symptoms were, sometimes hard trigger pull or maybe it wouldn't even pull at all, not able to pull the hammer all the way back in single action (again, sometimes), and an overall gritty feel. Going back and forth here suggestions ranged from tight chambers, to overly polished chambers, raised firing pin bushing, and on and on. Turned out to be the hand. It protruded forward and was catching the case rims. A local smith offered to take it in and fix it for $20 which I thought was pretty good. I ended up doing it myself though. Only took a few minutes. Ran about 350 rounds through it today and it was flawless. Now if I can get the trigger on it to be as nice as on my M27 I'll really have something.

Good to hear you got it sorted. Nice that you did it yourself.