If you are a Do-It-Yourselfer, then may I suggest that you purchase -
Jerry Kunhausen's book: "The S&W Revolver - A Shop Manual"
It tells all you need to know about the S&W revolvers.
The mainspring tensioning screw, also called the strain screw, will cause a condition called "knuckling" if it is backed off too much. If the tension is too light, the mainspring is too straight - which makes it too long. This causes the hammer stirrup to bind against the back of the hammer.
What I did for my revolvers was file down the top of the strain screw until I got the pull I liked, without taking off so much that it caused knuckling. I like this method best because if you want to return your gun back into factory condition, you just screw in an unaltered replacement strain screw (that costs $1.85 from S&W).
You can also get a reduced power mainspring from Wolff. I tried this method first, but it made my gun sound like a cheap kid's toy - the spring would make a tinny sounding "twang" that actually made me laugh the first few time I dry-fired it. Being too embarrassed to actually take this to the range - I tried the "file the strain screw" method and kept the factory spring in place.
Also, you can polish the factory spring until it is thinner, thus giving reduced pull, or, more recommended, "narrow" the spring, bringing the same results. It is my opinion that polishing the spring (which can heat it too hot, screwing up the temper) and "narrowing" should best be left to the experienced tinkerer.
I've also seen locking screws that keep the strain screw from backing out. This is where a hole is drilled in the bottom of the frame to the strain screw hole. The hole is tapped and then a screw that is long enough to reach the strain screw is installed. Now you have a locking screw. This method requires a bit of work on your part, but will keep the strain screw from moving.
Again, I found it easier just to file down the top of the screw.
See what the other forum members post here, and do what suits you best.
