I wrote in a previous post that on occasion the trigger on my 29-2 would not fully return. The consensus was it needed a new rebound spring. I did some research and picked Wolff's for the replacements. I figured while I had it open I would replace the mainspring with a Wolff's as well.

My NEW issue is that when cocking in single action the top edge of the rebound slide makes contact with the mainspring causing the action to bind. The hammer will go to the fully cocked position but it requires a "little extra" to get it there.

I removed the Wolff spring and put the previous spring back in and it works as it should. Is this just a matter of the Wolff spring needing to be "fitted" or did I get a bad spring from them?

If it is a matter of fitting would I bend the spring or relieve the top edge of rebound slide?

Is the Wolff spring a reduced power with the rib running down the center length wise?

If so, the added recess of that rib could now be making the mainspring strain screw too short to load (arc) the spring correctly so it clears the rebound slide.

Also, are you making sure the strain screw is tighten down all of the way?

The screw currently installed that's fitted to the factory spring crew may have been shortened, the strain screw is an 8-32 threaded screw, you can buy an 8-32 cap hex hex screw at a hardware store that's a bit longer that what you have to see if it does the trick.

See post numbers 4 - 8 in this thread: Best way to raise mainspring tension?

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Conrad
SWCA #1830 SWHF #222

I've installed several Wolff mainsprings in N frames and never encountered the problem you are describing. And that is both square butt guns like yours and round butt N frames too. And also includes traditional flat design Wolff mainsprings and the ribbed type they sell nowadays.

I just pulled the sideplate off of my 3 1/2" 27-2 and looked at the mainspring and the rebound slide and had no interference at all. This was with a stock flat mainspring. I then removed that stock flat mainspring and exchanged it with a ribbed Wolff type mainspring I had loose here and checked that out. And it still clears the rebound slide by a good 1/8" when going to full cock. And the guts of my 27-2 are the exact same as in your 29-2.

2 things come to mind. Are you tightening the strain screw down all the way? And have you or someone else ground down the end of the strain screw a little? The only other thing I can think of would be that Wolff sent you a mainspring with the wrong bend in it.

It is Wolff's "Standard Weight" spring and does have the ridge running along its length. After reading Gunhacker's post I looked at it again and can see that the strain screw rests in the valley of this rib.

I also looked at the surface of the screw where it contacts the spring itself. It does appear a little buggered up but I can not tell if it has been altered or if this is just normal wear from contact with the mainspring.

Another thing you can do is put the cup of a fired primer over the end of the strain screw as a temporary fix. This not only effectively lengthens the screw but widens the tip so it won't sink into the groove in the Wolff spring.

What is happening is exactly what gunhacker said, the spring isn't being arched adequately and is longer as a result. When you cock the gun the end of the spring is stubbing under the hammer and physically blocking it. You are actually arching the spring from the hammer pushing on the hook end.

Regardless, my suggestion is to simply keep the stock spring in the gun, it works the way the gun was designed to!

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Gunsmithing since 1961

All above are correct. You can get this same effect by loosening the screw. You will get to a point where it "binds".
Try Alks primer cup trick, it works everytime.

Thanks to all of the input from other forum members I have identified the strain screw as the culprit. I was able to make a shim (for testing purposes only) and everything worked as it should.

Now on to finding a new strain screw. I can find them for round butt 29's but the screws for square butts seem harder to find. Is the difference that significant?

Yes, the ones for round butt N frames are considerably shorter and will not work. I would give it up and put the original spring back in, since it works fine. No reason to put an aftermarket spring in.

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Richard Gillespie
FBINA 102

The strain screw will need to be replaced no matter which spring I use as the previous owner has altered it. While it does function with the spring and strain screw it came with I am concerned about the possibility of misfires from light strikes. I need it to go bang every time I pull the trigger as I intend to use the 29 as a woods gun when travelling in northern Arizona's bear country.

Look on eBay. Type in "n frame square butt strain screw" in the search box and the first thing that came up for me just now was a blue finish strain screw for you.

As a temporary fix, try a spent primer over the end of the strain screw. I've never tried it but those that have have had success.

Thanks muddocktor, screw has been ordered.