My way of doing it goes like this. Replace the strain screw with a #8 - 32 x 1/2" long set screw (headless). Start out too light on the mainspring tension.
1. Go to the range and shoot your ammo (the primers you will be using), and dial the tension up in 1/8 turn increments until there are no more light strikes. Then add another 1/8 turn for insurance against that 1 in 100. If you are shooting later and have a misfire, turn it up another 1/8 turn. Measure the hammer pull (not trigger pull, just the hammer) just where the hook comes off the frame with your trigger pull gage and record the number of ounces. Save this number and the gun it relates to for future reference. The brand of primers you're using will determine how light or heavy this number is.
2. Take out the set screw and put blue Loctite on it and put it back in, duplicating the previous hammer pull weight. OR file a stock strain screw to duplicate the hammer weight with the head tightened firmly.
3. Then try different rebound springs to find the one that returns the trigger the way you want it. Some people will want the lightest possible, some will want the hardest return, some will want something in between.
By tuning this way, you will get the lightest action that works how you want it, not just what someone else gives you. You are in control of the process, and it only costs a few bucks for a setscrew and allen wrench and a rebound spring assortment.
