610 light primer strikes, have installed springs and new pin, still not firing

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LBGunner

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I picked up a 610, decided to install a Wolff trigger kit. I installed the 'power rib' mainspring and the 14 lb trigger spring. There is also a 13 and 15 lb spring in the kit, I have not tried these yet. Rounds did not fire, very light strikes visible on the primer.
So I picked up an extended Apex firing pin thinking this would solve the problem. Went to the range today, still getting light strikes and rounds not firing.
The stock strain screw is all the way in, I am using the moon clips included with the gun, and I am using Winchester primers. The stock mainspring and pin were fine, all ammo lit off. I am using my own reloads.


So, the question I have for the pros on this board is: what do I do now? Do I get a set screw and take out the stock strain screw for the mainspring, get it to where it fires and file it to size?



Thanks for you all's input.
 
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You are on the right track. The Wolff Power Rib spring needs a longer strain screw due to the indentation of the spring.

You have a few choices.

Wolff sells a longer strain screw. You can put that in as is or file it shorter to get a lighter trigger pull.

You can use a #8 - 32 set screw (1/2" long for square butt or 3/8" long for round butt) with either #222 purple or #242 blue Loctite to hold it where you set it. These Loctites don't need any heat to adjust the screw. A setscrew has no head, so you can run it in or out as needed.

What I do for my match guns is to clean the hole and screw with solvent, put enough Loctite on both to cover the threads, and screw it together. Then mop up all excess Loctite with a paper towel and Q tip. Once that sets up, you can give the spring more or less tension simply by dialing the setscrew in or out. I start with it getting misfires, then tighten 1/8 turn at a time until I get 100% ignition. Then another 1/8 turn for insurance. Then I use an 11 LB rebound spring for the trigger return. This give a nice DA trigger for very little effort. Then I lube all contacting parts with Lucas Extreme Duty gun oil with a needle oiler, with just a drop on each part that slides or pivots.

YMMV. Other people will have other opinions.
 
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Loosen the strain screw. Place a spent primer (anvil removed) over the strain screw where it contacts the spring. Tighten the strain screw and see if that solves the problem. If so, order a new strain screw. They are fitted to give the proper amount of spring tension by filing the end of the screw that contacts the main spring. All you are doing is adjusting the length to ensure reliable ignition. A little long is way better than a little short.
 
I had trouble with a italian 1873 clone pressuring unreliably. Someone had ground off the side edges of the main spring I suspect to make it feel smoother. Strange because the piece looked absolutely unfired or untouched throughout. I replaced the main spring with a factory original, and switched to mag primers. Works better now.
 
Welcome to the S&W Forums. The leading causes of misfires with S&W revolvers stems from three things.
1. Strain screw backed out, either from recoil or trying to use it tune the trigger pull.
2. Strain screw shortened in an effort to tune the trigger pull.
3. Installation of an aftermarket main spring.
Put the factory main spring back into your Model 610. A lighter trigger pull can be achieved by installing a lighter trigger return spring, but that will also make the trigger return less positive. The best trigger tuning comes from skill with stones, polishing the engagement surfaces of the lock work, but that is not something to be done without a thorough understanding of how the lock work functions and proper tools for getting the angles correct.
 
The first and easiest thing to check is primer Seating ...
Make danged sure the primers are seated all the way down into the primer pocket untill they bottom out ... turn the case 180 degrees and seat it some more ... the primer must be at rock bottom of the pocket ...or
Light Strikes !

This gave me fits untill I learned the seating tricks .
Gary
 
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In my experience the bottom of the counterbore, where the screw head seats, is usually created with a drill. So not flat. If you can figure out a way to put a little angle on the underside of the screw head, the tip will extend farther. If you have a friend with a lathe, they could do it easily. I've also done it using a drill press and file, very carefully. The key words are always very carefully.
I did this a couple times when a friend was under a time crunch and needed a fix without waiting for a new screw to arrive..
OP, if you were close to me it would take only a few minutes.
The comments above about primer seating are correct. Federal primers are easier to set off than WW or CCI in my experience.
Good luck.
 
Thanks to all who weighed in with useful advice.
I bought an Apex firing pin and some #8 - 32 set screws 1/2" long, used blue loctite.
Runs like a top now.
And for the purists that love to stick to stock make note the trigger is much improved over stock. If you want to yard on a 14 lb trigger in DA that is your choice, I'll take 9 lbs and a tighter group.
 
LBGunner said:
I picked up a 610, decided to install a Wolff trigger kit. I installed the 'power rib' mainspring and the 14 lb trigger spring. There is also a 13 and 15 lb spring in the kit, I have not tried these yet. Rounds did not fire, very light strikes visible on the primer.
So I picked up an extended Apex firing pin thinking this would solve the problem. Went to the range today, still getting light strikes and rounds not firing.
The stock strain screw is all the way in, I am using the moon clips included with the gun, and I am using Winchester primers. The stock mainspring and pin were fine, all ammo lit off. I am using my own reloads.


So, the question I have for the pros on this board is: what do I do now? Do I get a set screw and take out the stock strain screw for the mainspring, get it to where it fires and file it to size?



Thanks for you all's input.
Click to expand...
No one in this thread has mentioned the other potential culprit: Headspace!

The 610 is designed to headspace 10mm rounds on the case mouth. If firing 40 S&W then the moon clip provides headspace. The factory moons are 0.035" thick. In my experience that is too thin, they should be 0.040". Long ago Scherer made such clips but now out of business.

With empty cases on a moon in the closed cylinder, measure clearance between case heads and breech face. I like about 0.007". Over 0.010" things get unreliable.

It is possible S&W got this wrong when they built this particular gun. While quality control was better in the past, I had to return a brand new 929 because of excessive headspace. S&W machined off the back of the ejector and stretched the crane to move the cylinder back, then replaced the barrel to restore cylinder gap.

Another hint is to measure hammer tension with a trigger pull gauge. At close to full extension the hammer should take a minimum of 3 pounds to hold it back in order to fire Winchester primers, and 2-3/4 pounds for Federals. These numbers were worked out for the original nose mounted firing pins. Best to be a little heavier for frame mounted pins.

Good Luck
 
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