While you may be able to lighten your revolver's trigger pull a little with a mere spring change, this is a job better placed in the hands of a talented and revolver-experienced gunsmith.
It's not just a matter of lightening spring pressure. It's also necessary to square-up, flatten or better-curve, and polish some surfaces.
Don't try this at home!

Mr. Ruger: I concur with steve1911a1 on his advice. A new set of lighter springs, if you are competent enough to install them, will make an improvement to the sa & da trigger pulls. If you are willing, contact brownells and purchase one of jerry kunhausens "colt shop manual" based on the recommendation of brownells tech department, for your particular model.

However, if you are not familiar with the action & do not have the proper tools to service it, i would advise you to contact mr. Teddy jacobson @ actions by-t or alex hamilton @ 10-ring precision on the internet and consider one of these fellows doing the work for you. Alex & teddy are both rated in the "top 100" by american handgunner magazine.