anyone weigh trigger pull during spring changes on 617?

markush

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I have a 617 inbound and have been reading all the info I can find on the 617's trigger on many different forums. I have yet to find a post where someone has taken the time to actually measure trigger pulls before, during, and after changing the springs.

What got me thinking about the numbers is the fact that you cannot change out the mainspring for the Wolff reduced power mainspring without using a longer screw in place of the factory strain screw. The longer strain screw increases preload on the mainspring and in my mind that is equivalent to using a heavier mainspring...no?

My question is...Has anyone measured both DA and SA trigger pulls and have numbers to share on the following...the reduced weight rebound springs with factory mainspring...reduced rebound and Wolff standard power mainspring...reduced rebound and Wolff reduced power mainspring with the longer set screw in place of the factory strain screw...etc.?

I'm really interested to find out if the reduced power mainspring and longer strain screw actually provide a lighter trigger pull then the factory or Wolff standard mainspring..and by how much!?

If there are no numbers out there and someone wants to lend me their trigger scale when I do mine I'd be happy to share the numbers with the world. :D
 
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I can't measure the pull because my scale goes over the limit.

You don't need to change the strain screw.

Rimfires are harder to do becauce the rimfire is harder to get reliable ignition.

You can tune the main spring by bending it. The flatter the spring the stronger it is.

Change the rebound to around 14-15 LBS for an improved DA pull.

Check out the faq above.:p
 
Thanks 500 Magnum Nut, I skimmed through the FAQ 3 times and didn't catch anything that pertained to pull weights with after market or factory springs?

I'm not looking for a "how to" I'm just curious if anyone has documented their trigger job and can share numbers.

With Wolff spring kits costing about $15 plus shipping I don't think I'll be bending springs and guessing at what I'm getting.

It is all over the interweb that with the Wolff reduced mainspring in a 617 you will get FTF unless you use a longer set screw in place of the factory strain screw to fine tune the preload. A socket head #8-32 x .5" set screw to be exact.
 
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Quote: I'm really interested to find out if the reduced power mainspring and longer strain screw actually provide a lighter trigger pull then the factory or Wolff standard mainspring..and by how much!? Unquote

Why do you want to add a longer strain screw with a weaker spring? Your defeating the purpose of a reduced power spring.

On factory springs: Whenever I open them up I tap the spring flat on the table. This gives the spring it's full power tension.

If you want a weaker tension on the full power mainspring: The springs are bent to alter trigger weight. Or you can grind then thinner on the sides to reduce the springs strength.
Or you simply back out the screw until the gun misfires, then go back in 1/4 turn, then add blue lock tite to keep the screw from un turning (bubba way).

The factory springs are tuned to what works best. Then the end of the screw is filed down to hold that screw length (professional way). Then the screw is fully tightened down maintaining that setting. There is a topic in the faq that talks about "Testing the hammer spring".

Rebound springs from the factory are rated at 18LBS. Wolff sells reduced power rebound springs. I don't recommend cutting coils here.

How I do trigger jobs? I maintain the factory full power spring and tune it if necessary. Then I add a reduced power rebound spring. This with polishing the correct places and adding lube to the proper places reduces the DA trigger pull. If the owner wants it even lighter, then I file 3/32 or so behind the thumb release, then I cut 2 coils off the bolt spring plunger (so the bolt can slide further to the rear, when the cylinder is closed). What this does is takes tension off the cylinder. Drag removed here translates to a lighter DA trigger pull. I don't mess with the springs inside the cylinder.
Reduce drag where possible, along with changing spring and tuning the main spring will give you the best possible trigger pull.
If you want to alter the SA trigger pull, this is done by stoning the trigger. This is covered in the FAQ under "fixing push off"

There is a good video from Jerry Miculek that covers some of what I talk of.
Other sources are from the S&W armorers manual and AGI (American Gunsmithing Institute).
Best of luck tuning yours.

 
The reduced power Wolff mainspring MAY FTF with the stock strainscrew. Replacing the stock strainscrew with a socket set screw allows you to adjust the mainspring tension easily for the least preload (the strainscrew adjusts mainspring preload) for consistent ignition. 290 loctite works well to keep it from moving. When you shorten or install a longer STOCK strainscrew you are adjusting mainspring preload THE EXACT SAME WAY. I use a Wollf 11 lb rebound spring shortened (clipped) 1 or 1 1/2 coils. My SA pull is 1 3/4 lb, DA is ~7 1/2 lb (on a 617-1) depending how the strainscrew is adjusted for the ammo I'm using. How much mainspring preload is required will vary with different ammo. You need to shorten the firing pin spring also to minimum preload, so it just holds the firing pin retracted. The "new style" RF FMFP guns will require more mainspring preload than the "oldstyle" crosspinned firing pin bushing guns.
 

Why do you want to add a longer strain screw with a weaker spring? Your defeating the purpose of a reduced power spring.

That's what I was thinking. If you have to increase preload on the spring at what point does that lightened spring become the weight of a factory spring and as such are you really getting any benefit of using the lighter mainspring?

Thank you for taking the time to write that out for me! It's the most comprehensive explanation I have read of how a professional trigger job is done on these revolvers.



My SA pull is 1 3/4 lb, DA is ~7 1/2 lb (on a 617-1) depending how the strain screw is adjusted for the ammo I'm using. How much mainspring preload is required will vary with different ammo. You need to shorten the firing pin spring also to minimum preload, so it just holds the firing pin retracted.

Are you and 500 Magnum Nut getting the same end result but the "adjustable strain screw" is saving the work of reworking the mainspring like he does? Or are you in fact taking it to the next level and reducing pull even farther by using the reduced mainspring?

It is a 617-1 that I will have in my hands today or tomorrow. Can you give me an idea of how much should be taken off the firing pin spring...should I start at one coil or...? Being that I am in Kenosha would it be possible to call on you if I needed some help?
 
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The reduced power mainspring does give the chance to have a lighter DA pull. Many use a stock mainspring that's recurved (bent). When you recurve the stock spring you change it's rate because it becomes shorter. If you just decrease preload (shorter strainscrew) the springs installed length becomes longer (it's less curved) and this screws up the hammer link (or stirrup) angle.
Sure you want to shorten your firing pin spring? It will allow less mainspring preload and a somewhat lighter DA pull, but on a 617-1 requires driving out the crosspin and firing pin bushing and very carefull alignment of the bushing during reassembly.
 
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Sure you want to shorten your firing pin spring? It will allow less mainspring preload and a somewhat lighter DA pull, but on a 617-1 requires driving out the crosspin and firing pin bushing and very carefull alignment of the bushing during reassembly.

Ha Ha I don't know...you mentioned it and I figured while I was in there...why not? Honestly I doubt I would need to. I had only planned on doing a 13 pound rebound spring along with the reduced power mainspring and set screw to take care of any FTF's that may give me. Other then that just a polish of the rebound slide.

Now if someone could give me numbers saying how much lighter the DA pull could be from driving out crosspins and bushings to get to the firing pin spring to lighten it and reduce mainspring preload I might consider it worthwhile. ;)
 
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