Installed this on a Smith 351 PD (22 Magnum J frame). Reduced the double action trigger pull from approximately 17 lbs to 10.5 using the heavier of two supplied hammer springs. Single action went from 2.5 to 2. So far, reliability has not been compromised in 50 rounds. As rimfire needs a heavier hammer strike for reliability, I’m very happy with this. Kit worked great!