jeremiahm, The mainspring (AKA hammer spring) is located inside the mainspring housing, not to be confused with the recoil spring. The factory mainspring is usually 23 lbs. Replacing it with a 18 lb spring lowers the sear friction, thus trigger pull and still provides plenty of hammer energy for a good primer hit.
Recoil springs are selected based on the power level of your loads. A 16 lb recoil spring is standard factory equipment. If you are shooting full power hard ball, an 18 lb spring is recommended. 22 lb springs are for +P loads. On the lighter side, if you are using 200 gr target loads, a 16 lb spring works well. Recoil springs are available in tensions from 10 to 28 lbs. The key for a proper recoil spring is function. If the spring is too heavy, the cases won't extract. If it's too light, you'll batter the gun. Also, lighter springs may not allow the gun to feed properly. Generally, you should use the heaviest spring possible that allows flawless extraction. Recoil springs compress with use and should be replaced every 500~1000 rounds.
Frame battering comes from not having enough spring tension in the recoil spring. As the slide bottoms out on the frame during recoil, it will beat the poor thing to death. Cracked slides and compressed springs may also result.
Trigger springs (AKA 3-finger springs) don't really come in lighter tensions. They must be shaped (bent) to conform to the specific gun. Seldom do "drop-in" springs actually drop in and work properly. Most factory guns come with the tension set way too tight.
To "adjust" the 3-finger spring: first, remove the slide assembly, thumb safety, mainspring housing, and grip safety, then flip the hammer strut up. Make sure there is no oil on the parts when making adjustments.
Center finger: with the 3-finger spring in place, slide the mainspring housing up until the pin hole at the bottom of the grip frame line up with the hole in the MS housing. Note how the center finger pushes forward against the ramp of the disconnector. Locate the disconnector on top of the frame. The proper tensioned center finger must provide enough pressure so the disconnector pops up after pushing it down. If this isn't set right, the gun won't shoot. You can take the spring out, bend the center finger and keep trying until proper tension is set. The optimum condition is when the disconnector pops up reliably with minimum tension.
Left finger: The left finger of the 3-finger flat spring controls the tension for the sear to latch the hammer when the hammer is cocked. If it is set too light, the hammer will fall when the slide slams forward. Full auto may result. Of course too much tension will make the trigger pull to harsh. A good starting point is to bend the left finger until it follows the same parallel as the center finger. Completely reassemble the gun and release the slide by pressing down on the slide release. The hammer must stay cocked when the slide slams shut. You can disassemble, bend the left finger back a little, reassemble and try again. The optimum is when the left finger has the minimum tension required to hold the hammer cocked when the slide slams shut (no ammo).
Right finger: The right finger controls the tension on the grip safety. Too much tension will make the grip safety bind on the trigger bow. Too little tension disables the grip safety. Bend the right finger until the bottom lip of the grip safety rests firmly on the lip of the mainspring housing. With the hammer cocked, the grip safety should move freely and spring back fully after being pressed.
The gun should now have a 3~4lb trigger pull. Removing "creep" requires buffing friction points and mating surfaces. This is a good way to get in trouble and ruin parts, not to mention possible full auto conditions.
Replacing the sear, disconnector, 3-finger spring, mainspring, and hammer are a good solution for Norincos and Chas Daly's. In higher quality guns, the parts are usually OK and seldom require replacement. The biggest culprit for creep is the sear notch in the hammer. If you decide to replace your hammer, make sure the replacement part is compatible with your grip safety, else it will not work. I like the McCormick kits because the sear and disconnector come pre-smoothed.
