I am looking at the Wolff Gunsprings website and they show J Frame hammer springs with available weights of 8 lb, 8.5 lb (standard) and 9 lb for centerfire revolvers.

For the rimfire revolvers they say the reduced power hammer spring is 9 lbs and that rimfire models 317, 650, 651 have a 12 Lb. factory standard hammer spring. They don't say anything about older J frame rimfires.

I have a pre-Model 34 that has a pretty stiff hammer spring. Has anyone tried an 8.5 or 9 lb Wolff hammer spring in an older rimfire J Frame ? 9 lbs is considered extra power for centerfires but reduced power for rimfires ? Are rimfires that much harder to ignite ?

I got a deal on a model 63 that misfired, replaced the aftermarket spring with the standard S&W .22 J frame hammer spring (easy to do with the coil spring) and have not had any problems since for several thousands of rounds. Suggest you heed Wolf's advice; yes, weak springs on .22s are very risky.

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Science plus Art

I use the 9# spring successfully in a 63 no dash and a pre-35 flat latch.