UPDATE: The replacement hammer spring was too long. Trimmed about 1/8"and it works fine.

I was replacing the springs in my neighbor's Model 60-9 S&W revolver. A nice "pre-lock" model!

I got the springs replaced and was putting it back together when I noticed that while it would fire in DA mode, I couldn't get it to lock back in SA mode.

Does anyone know what this might be?

They sent me an incorrect length mainspring. Replacing it fixed the issue.

Photo May 24, 11 54 15 AM by Dave Steier, on Flickr

This message has been edited. Last edited by: Rolan_Kraps,

Have you tried putting the old mainspring back in?

Yea, you can see the spring binding.
Are you sure it's the correct spring?
I've never had to trim a main spring.

The spring doesn’t look like it’s binding but rather highly compressed. Doesn’t look like there is any room for the hammer to cam back all the way to the single action notch.

I agree replacing the hammer spring in the picture with the original until you’re able to locate a correct replacement.

Coil bind occurs when the spring is compressed to the point that all the coils are in contact, and can not be compressed any further.

The photo clearly shows "binding".

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See original post.