I have tried replacing springs on my PM 9. I have used M Carbo and Galloway Precision. I got light strikes with both. Failure to fire was just too risky for my EDC. I just have to find a replacement for my PM 9. For me it is NOT just the trigger weight but the ridiculous long pull and reset. I know others love it but I just cannot get used to it. So far I only have about 1,000 rnds thru it and still just not working for me. I will replace it with some other DAO probably Sig 365 SAS when I can find one.