I finally found this from previous post:
Originally Posted by bumper View Post
Firstly, you can get a good idea of how "other things", besides the hammer spring, are affecting trigger pull and most especially "feel" by dry firing the weapon, then with trigger still held full back, push the hammer forward and hold it there. Next release the trigger while still holding hammer forward. Now you will be able to move the trigger through it's arc - the only things affecting the trigger at this point will be the trigger pivot pin, the trigger bar, the reset spring, and the sear spring at the very end of the trigger stroke. This all as it relates primarily to SA operation.
The main culprit of DA trigger weight is, of course, the hammer spring. Simple physics, with everything just as polished out and perfected as can be, an 18 lb Wolf hammer spring will get you into the sub-nine pound range, around 8.5 lbs is doable. Note that there will be some manufacturing variations in Wolf sping batches, typically less than a pound variation or so. But, if you get a 17 lb spring labeled as an 18 lb spring, that variation will show up as less pull weight. I test my springs to see what they really are. GGI gets their hammer springs from Wolf.
I did a write up on the effect of hammer spring strength on both DA and SA trigger weight on some other forum. I can go fetch a copy and post it here if there's interest.
Oh, forgot to mention, the sear to hammer fitment (stoning, polish, engagement depth and angles) will affect SA pull only. In the DA mode, the sear is held disengaged and the trigger bar cams against the hammer pin to drop the trigger bar out of the DA cocking notch on the hammer, which happens near the end of the DA trigger stroke.
bumper