I am restoring my collection that was in a flood and the last two were pinned and recessed Model 29 and 28.
What I found was a pin inside the rebound spring that causes the trigger to return.
I have done trigger work on plenty of Smiths and never ran across anything like this.
My thinking is it is supposed to stop the spring from binding like the full length recoil spring guide rods in semiauto pistol.
Anyone else run into this?