I took my GP100 out today for the first time since I changed the mainspring and the trigger spring. I went down two pounds on each. I shot over 50 rds with no light strikes or other issues. I shot some from a box of 130 grain .38s and some of the 158 grain 38s. I also changed my front sight to the red hi viz fiber optic sights. I love these things, if you have not done this yet, you need to get busy. I promise you its a thousand times better than the stock sight. I had to do no adjustments to the rear sight either. I am perfectly satisfied now with these changes and the polish job done previously, this gun ain't going anywhere. I have several Smiths and two Pythons. While the action is not close to the Pythons it is every bit as good as the Smiths. And I while I have shot groups just as tight with the Pythons, I have yet to shoot such a group with the Smiths. I like them all but I would sell all the Smiths and keep the Pythons and the GP100 if I had to choose.
Anyway I shot this group today from 21' no rest and it is a 3" bullseye. I am not a great shot by any means but this is my best from the GP100 so far.