First of all, what's the problem with the trigger?
I am going to assume that you can live with a two stage trigger if the final stage provides a clean release.
I may be wrong about this.
The first thing to do is purchase a new 20 pound Wolff mainspring.
http://www.gunsprings.com/RifleShotgun/Springfield_RsNF.html
Your factory mainspring is over 60 years old, and maybe it was 16 pounds then, but it most certaintly is not 16 pounds now.
Just replacing a worn out mainspring with a new mainspring will often bring back a crisp second stage release.
I do have a bias. I like military two stage triggers. I believe that they are the most reliable and shockproof of any trigger mechanism. Shoot enough rapid fire stages and you get quite used to taking up the first stage without noticing.
If the mainspring does not fix a creepy trigger problem, replacing the old one is still a good idea as it will speed up the firing pin.
If you have to have a single stage trigger, a Timney is as good as any other.
It is not difficult to install. If you do not have the mechanical competence to remove the old trigger and install a Timney, and lets be honest about this, then ask for assistance. The installation of a single stage override trigger sometimes is simple, and sometimes takes tweaking. Tweaking is best done by someone who has a high mechanical aptitude.
