Howdy
First off, do not use steel wool on your Single Six. Not even 0000 Steel Wool. Unless you are extremely careful, steel wool will cut through the blue.
The post to use a copper cleaning pad is a good idea, but some 'copper cleaning' pads are actually steel, with a thin layer of copper on top. Once you wear through the copper layer, you will be scrubbing the gun with steel wool and you will be cutting through the blue.
Instead, I recommend using Bronze Wool. Bronze wool will not harm the blue. Used with thin oil you can remove most of the crusty rust with bronze wool.
You can buy bronze wool from Brownells. Yes, it is expensive, but I never use steel wool on any good firearm.
https://www.brownells.com/gunsmith-...brasives/metal-wool/bronze-wool-prod7391.aspx
What is a Three Screw Ruger?
Just like a Colt, the first SIngle Sixes and Blackhawks had three screws that the lockwork parts pivoted on. One each for the hammer, one for the trigger, and one for the bolt.
The mechanism of the old Three Screw Rugers functioned just about the same as a Colt. The major difference was the Rugers all had a frame mounted firing pin, and all the flat, leaf type springs of a Colt had been replaced by coil springs.
At the top of this photo is a Three Screw 44 Magnum Blackhawk. At the bottom is a 45 Colt New Model Blackhawk. In Ruger Speak, as far as single action revolvers are concerned, New Model means it has a transfer bar in place. Notice the New Model does not have screws for the parts to pivot on, instead the hammer pivots on one large pin and both the trigger and bolt pivot on one smaller pin. (don't get me started on Vaqueros and New Vaqueros, which are all New Models with a transfer bar inside.)
Here is the same 44 Mag Three Screw disassembled. I have lined up the three screws for the hammer, trigger, and bolt near their respective parts. Notice too the coil springs. Ruger has always used coil springs because they are less likely to break than the leaf type springs traditionally used in a single action revolver. By the way, the grip frame of the old Three Screw Rugers is aluminum with a hard anodize coating on it. There should not be any rust on the aluminum grip frame, but you can clean it up with bronze wool and thin oil. Do not rub too hard are you will go through the hard anodize and expose the shiny aluminum underneath.
Here is a close up of the lockwork parts of a Three Screw Ruger. Notice there are three cocking notches on the hammer, one for the so called 'safety notch' one for half cock, and one for full cock. The full cock notch is all the way at the bottom of the hammer, it really is not much more than a bump. While we are at it, notice how thin the tip of the trigger that engages the hammer notches is. More about that in a minute.
Here is the 45 Colt New Model Blackhawk from the first photo, disassembled. Notice there are a lot more parts than in the Three Screw. The vertical piece attached to the trigger is the transfer Bar. The two pins above the grip frame are the pins the hammer, trigger, and bolt rotate on. There are only two positions for the hammer of a modern Ruger like this, full cock or all the way down.
This photo shows the transfer bar. Notice it is partially covering the frame mounted firing pin. Sorry for the crud in the photo. When the hammer is cocked, the trigger rotates back slightly, pushing the transfer bar up so it can Transfer the blow of the hammer to the frame mounted firing pin. True to its name, a transfer bar transfers the force of the hammer. It is not a Hammer Block. A lot of shooters get confused about that. When the trigger is released, it pulls the transfer bar down so it no longer can transfer the hammer blow to the firing pin. The hammer rests directly against the frame when the transfer bar has been withdrawn. That is why a modern Ruger with a transfer bar is completely safe to carry fully loaded with a live round under the hammer. Just like a Colt, the old Three Screws were not safe to carry fully loaded with a live round under the hammer. Go back and look at the photo of the lock parts of the Three Screw. Just like a Colt, that thin tip at the top of the trigger could shear off if the hammer spur received a sharp blow. This could drive the hammer forward with enough force to fire a live round under the hammer. After losing some expensive lawsuits brought about by shooters who did not understand this, Ruger completely redesigned all their revolvers in the 1970s to include a transfer bar.
I would not dream of sending any of my Three Screw Rugers back to have a transfer bar installed. Yes, it will affect the trigger pull, it has to. Just like with a Colt, the trigger just moves a little bit to release the hammer from full cock. The trigger in a transfer bar equipped Ruger has to travel further because the motion of the trigger is what raises the transfer bar. Instead, I load all my old Three Screws the same way I load a Colt. Put the hammer at half cock, open the loading gate, load one chamber, skip one, load four more, draw the hammer all the way back and carefully lower it. If done correctly the hammer will be down on an empty chamber.
Interestingly enough, Three Screw Rugers have the screw heads on the right side of the frame. Colts have always had the screw heads on the left side of the frame.
