Best spring upgrades for a rimfire....

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I'm only familiar with Wolff and Wilson for hammer/rebound spring upgrades in the S&W revolvers. I'd like to try to improve my model 17's trigger pull a bit. IIRC, Wilson doesn't recommend their spring kit for rimfires and am not sure about Wolff. Anyone have any experience with some aftermarket spring kits that they would like to share? Thanks.
 
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Personally, I think you're better off with the original S&W mainspring for rimfires. It's a stronger spring, and can hit harder if needed. You may be able to use a lighter rebound spring. A lot of times, you can take a couple of pounds off the trigger pull that way. Get some Wolff ones from 11 - 15 lb. and find the lightest one that works after the mainspring is setting them off 100%.
 
I use Wolff standard springs in my 617’s and k22. No issues with FTF. 14 lb or 15 lb rebound springs. Wilson Combat springs on all center fire revolvers.
 
Personally, I think you're better off with the original S&W mainspring for rimfires. It's a stronger spring, and can hit harder if needed. You may be able to use a lighter rebound spring. A lot of times, you can take a couple of pounds off the trigger pull that way. Get some Wolff ones from 11 - 15 lb. and find the lightest one that works after the mainspring is setting them off 100%.

I agree with you, but my suggestion would be to go one step farther as this has worked for me for over 45 years. This would not be recommended for any self defense gun obviously, just for target shooting and range uses.

One can buy a bunch more Main Spring Strain Screws to custom shorten a small amount while still using the original Main Spring. Do not alter the original screw so it can always be put back - no harm, no fowl. Yes - I am aware that Rimfire hits need to be a littler harder than Centerfire, however most times you can decrease the weight a bit and still have 100% reliable ignition. This may take a few try's and that is why I suggest buying several extra screws - they are certainly cheap enough. Different lengths will produce less weight pulls and when you find the perfect weight and get 100% ignition but still reduce pull weight, you have been successful.

While you can never get a Rimfire as light as a Center Fire, you can successfully do this as I have done it quite a few times with 100% reliability. With the addition of a lighter Rebound Spring you should have a pleasant shooting Rimfire Revolver.

NOTE #1 Always shorten the screw and tighten fully. Never leave a standard length screw partially backed out and loose.

NOTE #2 Put the original length factory screw in a small plastic bag with a note explaining what it is. This way if you sell or give the gun to someone, they will know what the screw is for and how to restore the Revolve back to Factory spec's. If you do change the Rebound Spring, put the original in the bag as well and store in the original box or pistol rug.
 
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How are the aftermarket main springs that are rated at factory power, such as the Wolff type 1? Do they have a different geometry that improves trigger pull, but still maintains the factory power?
 
The aftermarket ones are not as stiff as the original. The type 2 Wolff is just a bent type 1. The bending gives it less preload with the same strain screw setting, therefore a lighter trigger pull. Also, the "Power Rib" goes down to where the strain screw fits into it, effectively giving you a shorter strain screw.

The Wilson spring is a bit shorter than the Wolff or S&W. This pulls the stirrup more parallel to the rebound slide, giving a lighter trigger pull with an equivalent hammer pull. The others pull the stirrup up at about a 45 degree angle, and it takes more force to bend the spring downward as it goes forward. The Wilson spring only has to go forward without bending down.

I use a #8-32 socket setscrew for the strain screw. A 3/8" long for round butt or a 1/2" long for square butt. The setscrew must be retained with either #222 purple Loctite or #242 blue Loctite. Doing this holds the screw in place, but allows easy adjustment or removal at any time in the future.

For those who want a regular strain screw with a head, you can use the setscrew to adjust to the spring tension you want, measure the hammer pull weight with a trigger pull gage, and shorten one strain screw to get the same hammer pull weight. Then you don't need a big pile of strain screws, just one.
 
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For my 617-6, I had to do something because out of the box the trigger was super heavy, one only a lawyer would love. So I went with a Wolff Power-Rib mainspring and a 13-pound trigger return spring.

I did have a lot of misfires initially with the mainspring, so I got an extended strain screw from Wolff. I then measured the length difference between the regular strain screw and the longer one, and then measured the depth of the depression in the Wolff mainspring. I then shortened the extended screw (using a Dremel) so that I could tighten it down fully into the depression in the mainspring. This took care of all the misfires, and I have a great DA trigger pull now.
 
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