hammer spring replacement question

[atlatl]

I have changed hammer springs and rebound slide springs on several Smith & Wesson revolvers with generally good results. On both of my N frames, I installed a wolf reduced power hammer spring- but then had to obtain a longer strain screw to provide enough tension to get it to be fully reliable. The double action trigger pull is now somewhere around 9 pounds.

I'm about to swap hammer springs on a 686 and I'm wondering if there is any reason not just to shorten the strain screw, rather than put in a lighter spring and then need a longer strain screw? What is the downside, if any, to just taking tension off the factory spring to achieve a 9 ish pound trigger pull?

Thanks

 

[minconrevo]

Truing the hammer fall and trigger action is part of a really good S&W revolver action job. That partly involves placing just enough Powers shims, in the respective positions, to keep those two parts from touching the frame, at any point of their travel. The mainsprings that have the "power rib" may or may not require a longer strain screw. Personally I like the "feel" of the power rib as opposed to the stock mainspring or the bent arm version of it.

 

[robertrwalsh]

If yours has the newer stirrup on the hammer that presents issues. It isn't like the older design when you start diddling with the springs.

 

[Baltimoreed11754]

I’ve always heard that backing out the strain screw was a poor way to lighten the trigger on a Smith so I’m not sure what you’re asking. Having a longer screw that could be moved in or out until you had light strikes or did not have light strikes would be better? Not a S&W armourer by any means but I’ve been into my 617-10 way too much tinkering and experimenting with springs. My last iteration seems to work with a removal of the mim stuff, a K22 hammer, a longer allen strain screw, standard flat mainspring, a lighter trigger return and a smooth K frame target trigger. The wider target trigger makes up for the heavier trigger but this is a .22 so I would think a cf would not have a lot fewer issues with light strikes.

 

[Dump1567]

One of the video's I've watched of Jerry Miculek doing a trigger job involved shortening the strain screw. Obviously testing for reliability with your carry ammo is a must.

The Gunsmith Nelson Ford has some good You Tube videos describing what he does for triggers. In one video he has a chart for what the hammer weight should be for reliably ignition. It's different for hammer guns (Pre-96') and firing pin guns (Post 96'). One of the video's shows how he measures the weight.

Personally, I usually just replace the rebound spring, as most of my Revolvers might be a carry gun. And don't want to tune it for certain primers.

 

[atlatl]

Perhaps I did not ask my question specifically enough. Is there an advantage or disadvantage to keeping the stock main spring but shortening the strain screw to achieve a 9.5 pound trigger pull, versus putting in a Wolf reduced power main spring and then having to use a longer strain screw to achieve enough tension to get the same 9.5 pound trigger pull?

As it was brought up above, but I am unfamiliar with any issues regarding it, my hammer does have the new stirrup design. How does that impact the spring change?

Thank you for any advice.

 

[TheTinMan]

+1 on hammer and trigger shims for improving the action.

As far as I know, the Wolff hammer springs are designed to work with a stock length strain screw. I have never had ignition problems.

I have read that Wilson’s hammer springs are better than Wolff in terms of reliable ignition but haven’t tried one yet.

 

[WR Moore]

Per their claims, the various reduced power mainsprings are supposed to be reliable when used with the stock strain screw. However, there's variation in if your screw is for round butt/square butt. AND the OAL on the screws seems to vary more than it used to.

Now, slight detour: springs let down somewhat after installation and going through a number of compression/flex cycles. So you don't want to be too picky about exactly what your initial trigger weight is right after changing springs. You also have to realize that N frame parts are heavier and given all the various friction points, takes careful work on various parts to reduce excess friction. It's most unlikely you'll get it as light as a K frame.

Back to the strain screw: get several and AFTER your springs have worked a bit, you can carefully back off the strain screw and see what happens. When you get misfires, tighten the screw about 1/2 turn. Then, make sure that's reliable. At that point, you can count the turns to fully tight. Each turn of the screw is 0.031 inches. Shorten a screw the appropriate amount, tighten fully and try it.

 

[sceva]

I have changed hammer springs and rebound slide springs on several Smith & Wesson revolvers with generally good results. On both of my N frames, I installed a wolf reduced power hammer spring- but then had to obtain a longer strain screw to provide enough tension to get it to be fully reliable. The double action trigger pull is now somewhere around 9 pounds.

I'm about to swap hammer springs on a 686 and I'm wondering if there is any reason not just to shorten the strain screw, rather than put in a lighter spring and then need a longer strain screw? What is the downside, if any, to just taking tension off the factory spring to achieve a 9 ish pound trigger pull?

Thanks

I had a Wolff std power spring in an N-Frame I used to have. Got a smoother double action pull with it while still getting reliable ignition. The only issue I had with the Wolff springs was the power rib they formed up the centerline of the spring. being hard on the tip of the strain screw. I like Wolff in a lot of things but I'll stick with stock S&W mainsprings.

 

[nksmfamjp]

I’m not sure where you are getting a 9.5lb DA pull from. Lightening the hammer spring has a limit defined by primer reliability. Not worth it to me.

Lightening the rebound spring works best for me. That said, check by pulling the DA as fast as you can. Light rebound springs slow the DA reset. You can feel it. Always go a bit heavy on defensive or competitive guns.

I forget, but I think I’ve been happiest around 10.5-11lbs.

Shortening a strain screw works, but get an extra to shorten. So many have been messed with, it may be hard to find a S&W screw in the right finish unmolested!

 

[Bullseye Smith]

Changing springs is OK for a carry gun. For a target gun you need to take it to a Action Smith, not a regular Gun Smith. Thats like going to a toe Doctor for a heart problem. A action job on a double action pull should be the same amount of pull from start to finish and feel smooth as silk being pulled thru your fingers. That alone makes a revolver way ahead of a auto. I shot Bullseye with Double Action for years, learned from my second dad and my friend that was in the Performance Center, many years ago. It is a dying ark anymore. My pride and joy is a 686-5 that has a 3 pound Double Action that has a 9mm cylinder and a 38 cylinder that feel the same when you pull the trigger. It only shoots Federal Primers.