My Model 19-3 4" was giving me problems today. I was watching TV and dry firing when it kept "short stroking". I thought it was just me so I slowed down and made sure the trigger was coming all the way back. It still would get hung up, sometimes the hammer could not be pulled either.
I popped off the side plate and slowly worked the action. The sear points seem to doing their job just fine and I could not make the problem happen with the side plate off (I was going real slow).
From studying the action it seems that the only place it could be hanging up is where the trigger meshes with the cylinder stop. I sprayed some cleaner in there and oiled it and then put the side plate back on. The trigger return spring looked like it was doing it's job OK.
This seems to have resolved the issue for now. I guess there could have been some crud in there somewhere...
So.... when short stroking, is it in fact the trigger cylinder stop mesh point that gets hung up?