grob, Just stating some facts that many people overlook. First, I doubt if any shooter enjoys a harsh, heavy, or raspy trigger pull. What you don't want to do is sacrifice other accuracy attributes just for a lighter trigger pull. This is especially noteworthy for SA revolvers because of their long lock time.
Before decent accuracy can be achieved, the shooter must get a precise sight picture while holding the gun very stable, squeeze the trigger without moving the muzzle, and hold the sights on target until the bullet exits the barrel. The first two things ... sighting and trigger pull ... happen before the sear releases the hammer. The last thing is called lock time and happens after the trigger is pulled but before the bullet exits the muzzle. It's during the long SA lock time where most shooters anticipate recoil or jerk the muzzle causing the bullet to miss its mark. A typical SA revolver will have almost double the lock time of a DA revolver and triple that of a striker fired pistol and that's why lock time is so important for SA marksmanship. Long SA lock time is a product of a large heavy hammer with a long throw.
When you replace the hammer spring (mainspring) with a reduced power spring, lock time increases at a proportional amount. A typical factory hammer spring will be 23 lbs and a reduced power spring will be 17 lbs. This accounts for a 25% reduction in trigger pull and makes lock time 25% longer. With most shooters, this fools you because a lighter trigger should make the gun more accurate but in actuality, it is counteracted by longer lock time and ends up with worse groups. If you shoot from a bench rest, lock time is not a very important factor.
The very best way to reduce trigger pull is to shape the hammer's sear notch so the hammer is not cammed back or allowed to move forward when the trigger is pulled. This is called a perfectly squared trigger and will allow the lightest pull possible without compromising safety. Additionally, you can install a lighter trigger spring or modify the existing factory trigger spring for less sear tension. Once sear tension is lighter, you will feel a lot more movement or "creep", which is bad. To get rid of creep, buffing or stoning the sear notch on the hammer and the sear extension on the trigger will smooth the surfaces to a point where all you feel is a crisp sear release. There's no need to alter the hammer spring if you do a "real trigger job" and I guarantee .... accuracy will be at its best with the factory hammer spring.
Two other issues are often overlooked when it comes to handgun accuracy and they are grip and sights. Personally, I find Ruger sights are pretty good ... maybe not perfect for all lighting conditions, but satisfactory. Because our eyes are so different, the next person may find factory sights are next to worthless. The primary issue with sights is simple and that is to get a repeatable sight picture.
The more stable you can hold the gun, the better your accuracy will be. With SA revolvers equipped with plow handle grips, it's quite a challenge to maintain stability through lock time. Many shooters go for grips with nice "looks" and can't figure out why they can't hit the broad side of a barn. Once you get some decent grips that fit your hands, it's amazing how accuracy improves. If you are really sensitive about looks ... put the pretty ones on for show and when you shoot, use the ones that fit you best.
Grips vs hands are like sights vs eye sight. Because our hands are not all shaped the same, a certain grip style may fit me perfect but not the next guy. There's nothing wrong with getting opinions on the forum but just because one person loves or hates a specific set, it doesn't mean you will.
When all things are considered for accuracy, grips make the most difference, then sights, and finally trigger pull. As
flat top said ... it's all in the SA Gun Guide. See:
http://rugerforum.net/miscellaneous/26246-new-iowegan-gun-guides.html