It's a late 1960's single six which came with the XR3-RED grip frame. I prefer and changed to the earlier XR3 size on the small frame .22. I added the S&W lanyard swivel which doesn't show that well because it's folded down in the photo.
The muzzle end of the 6 1/2" barrel had severe rust pitting so I bobbed it to 3 1/2" and turned it 90 degrees so the roll mark is on the side like the large frames and so the front sight wouldn't cover the front of the wording.
The front sight is a new model 22 ramp sight that I filed down to regulate it for the short barrel and re-serrated it like originally done from the factory.
The ejector rod housing is steel from a Colt clone because it has the curved rod slot. This allows the rod button to swivel away from the barrel and around the cylinder pin to more fully eject cases, especially the magnum cases.
The hammer is a new model Bisley 22 that I cut the base off of and silver soldered to the base of an old model hammer with its 3 notches.
The trigger is a wide old model super Blackhawk. I removed some of the width of the trigger near the top of the slot in the grip frame so I can install it in the grip frame sideways and turn it 90 degrees. Then simply install the grip frame and trigger on the gun as an assembly. On other projects including installing modified Bisley triggers in an old model, I just enlarged the trigger guard slot.
It's a very handy little field gun.