What do I need to get to lighten my 12 lbs NYPD trigger on 5946 smith?

A lighter mainspring (hammer spring) will lighten the trigger pull.

A caution is that some primers are not very sensitive and too light of a hammer strike may result in unreliable ignition of the cartridge.

Try a lighter spring but test it for reliability with your chosen defense ammo.

John

Stoning the sear would be the correct thing. Arkansas stone, but you need to know what you're doing. We always used a special fixture when working on the Mod 52. We never really checked trigger pull on anything but the 52 and the 41 unless something really felt weird, then we would just exchange parts.

Don, the OP was referring to a Model 5946, which is Double Action Only.

The sear does not release the hammer on that model.

Although "stoning the sear" might be the correct action to take to lighten a single action trigger on a TDA (DA/SA) or SA only model.

John

Well you learn something new every day. Those were not around when I was there. Never handled one. Never thought I would want a DA only gun, just seemed weird to me for some reason, but... I had an offer on a Ruger LCR 38+P DA only. An offer I couldn't refuse. That was the sweetest DA pull I ever shot. and at 13.5 ounces it's now my EDC gun.

Donk52 , I see you have a 469 there . What do you think of those ? Seems a little weird , working on 52's and owning a 469 . Forgive me for going off topic , just had to ask .

I could never afford a 52 when I was there. This 469,(I was told) was one of the first to be built, sent out to gun magazines for evaluations and photo op as the S&W "mini gun". I'm not sure if the ser. no. is within the standard 469 range. When it was returned it was well used. I rebuilt it and purchased it through an employee lottery. I probably paid less than $180 for it. But back on topic, I believe the the S&W trigger pulls are horrendous today because of Massachusetts compliant laws. I think they are supposed to be 10 lbs. from the factory.