https://www.shootingtimes.com/editorial/diy-smith-wesson-j-frame-trigger-job/473688
"Reduced-weight hammersprings are mostly meant for centerfire guns. Rimfire revolvers typically have stronger hammersprings to help ensure reliable ignition. For example, some rimfire S&W revolvers have 12-pound factory hammersprings. But they, too, can benefit from lighter trigger springs. If you're looking to lighten your rimfire's trigger pull, check with your gunsmith.
TK Custom and Apex Tactical have kits that include an extended firing pin and firing pin spring along with trigger and hammersprings. The longer firing pin is intended to ensure positive ignition.
The hammerspring has to be strong enough to reliably ignite primers. I tested this with TK Custom's springs and firing pin combo in the Model 60. I used 50 rounds each of handloads with CCI 500 standard and 550 Magnum Small Pistol primers.
I selected CCI primers because in my experience they tend to be the least sensitive of common handgun primers.Be sure to test your gun thoroughly with your preferred ammo after changing springs to make sure it fires reliably and also that the trigger returns reliably.
Changing springs is a quick way to reduce the trigger pull on your J-Frame."
