Light strike befuddlement

[AZAndy]

My S&W 325 was failing to fire once every six rounds or so in double action, although it always seemed to work fine in single action. So I replaced the mainspring. It was still doing it, so I put in a Cylinder and Slide extra length firing pin. Now it fails four out of six, and single action is no better. A second try will set off the round, but I'm thinking I'd like a bit more reliability than that. Anybody have any ideas?

 

[RealGun]

My S&W 325 was failing to fire once every six rounds or so in double action, although it always seemed to work fine in single action. So I replaced the mainspring. It was still doing it, so I put in a Cylinder and Slide extra length firing pin. Now it fails four out of six, and single action is no better. A second try will set off the round, but I'm thinking I'd like a bit more reliability than that. Anybody have any ideas?

I believe that would call the moon clips into question. Maybe try some thicker ones.

 

[AZAndy]

I believe that would call the moon clips into question. Maybe try some thicker ones.

Oooooh, that's a thought. I'm using Wilsons that are slightly not-flat on one side; maybe I could just flip them over. Thanks for the idea.

 

[Zendude]

I found that aftermarket grips can interfere with the action of the main hammer spring causing frequent light strikes.

 

[AZAndy]

I found that aftermarket grips can interfere with the action of the main hammer spring causing frequent light strikes.

Hmm. That certainly applies. It's wearing a cushy Pachmeyer. I'll take the grip off and look for scuffing on the inside. If that's the case, I'm not sure what I'd do about it-- I can't shoot it with wood grips (well, I can, but only once).

 

[Zendude]

Hmm. That certainly applies. It's wearing a cushy Pachmeyer. I'll take the grip off and look for scuffing on the inside. If that's the case, I'm not sure what I'd do about it-- I can't shoot it with wood grips (well, I can, but only once).

A cushy Pachmayr is the offender on my 38 right now. I am thinking of using a dremel to take a little material off the inside of the grip where it is rubbing on the spring.

 

[AZAndy]

A cushy Pachmayr is the offender on my 38 right now. I am thinking of using a dremel to take a little material off the inside of the grip where it is rubbing on the spring.

Thanks for the suggestion, I never would have thought of it being the grip. I'll check it out!

 

[straightshooterjake]

I wrote an article about working with springs and trigger pull in Smith & Wesson revolvers. It contains a lot of useful information if you have problems with light strikes.

The article is here:

Improving the trigger on Smith & Wesson Revolvers

The article is also discussed in this thread:

https://www.thehighroad.org/index.p...wesson-revolver-triggers-please-review.817407

The article has a section about spring strength and the causes of light strikes and a section about working with leaf mainsprings.

 

[ArchAngelCD]

You said in your OP, "a second try sets off the round." Are you firing handloaded ammo or factory ammo? If the ammo is handloaded it's possible the primers are not seated correctly. If it's factory ammo, just ignore this lol.

 

[AZAndy]

You said in your OP, "a second try sets off the round." Are you firing handloaded ammo or factory ammo? If the ammo is handloaded it's possible the primers are not seated correctly. If it's factory ammo, just ignore this lol.

They're reloads, but work fine in everything else.

 

[earplug]

Look at the end of your strain screw. I have had them mushroom and loose length. This caused misfires. I got hardened hex head screws from a hardware store. If you have a grinder/dremel you can fit them without issue. Or do what old timers did and cover the strain screw tip with a small primer cup.

 

[straightshooterjake]

What is the double action trigger pull weight on the model 325? The double action weight allows us to make a general estimation of the mainspring strength. And since a lack of mainspring tension is the most frequent cause of misfires, getting an estimate of the mainspring strength is very helpful for understanding this problem.

Also, what is the history of this revolver? Has it had trigger work? Did you buy it new? How many rounds have you fired through it? Did this problem suddenly arise?

The suggestion from Earplug to use a small primer cup as a shim on the end of the strain screw is a good one. If the mainspring tension is not quite enough, then shimming the strain screw often resolves the issue.

All of this, and much more, is described in the article I referenced above. I realize the article is quite long, but sometimes these problems are tricky, and there is a lot of info to cover.

 

[AZAndy]

Look at the end of your strain screw. I have had them mushroom and loose length. This caused misfires. I got hardened hex head screws from a hardware store. If you have a grinder/dremel you can fit them without issue. Or do what old timers did and cover the strain screw tip with a small primer cup.

Ah-ha! Took a while to get around to it, but I finally tried your suggestion. The end of the strain screw looked fine, so I emptied a spent primer and (after much fiddling) got it in between the screw and the spring this morning. Ran out just now and tried it out with 7 clips, and the light strikes were reduced to 3 out of 43 rounds. That's a heck of a lot better than it was doing before-- I put wood grips on it yesterday to rule out any binding from the rubber grip I usually use, and had a 75% failure rate. I'm thinking I'll increase the thickness of the primer shim with a bit of wadded aluminum foil inside it and see if that doesn't cure it entirely. Thanks muchly for the idea!

 

[AZAndy]

What is the double action trigger pull weight on the model 325? The double action weight allows us to make a general estimation of the mainspring strength. And since a lack of mainspring tension is the most frequent cause of misfires, getting an estimate of the mainspring strength is very helpful for understanding this problem.

Also, what is the history of this revolver? Has it had trigger work? Did you buy it new? How many rounds have you fired through it? Did this problem suddenly arise?

The suggestion from Earplug to use a small primer cup as a shim on the end of the strain screw is a good one. If the mainspring tension is not quite enough, then shimming the strain screw often resolves the issue.

All of this, and much more, is described in the article I referenced above. I realize the article is quite long, but sometimes these problems are tricky, and there is a lot of info to cover.

Thanks for the link to the article! It's been helpful in understanding the forces and variables at work. I got the thing used, and I have no idea how much it's been fired, or whether there's been trigger work. When I first got it, it would do a light strike one out of six or so, so I put in the new mainspring (Wolff standard power). Then it went up to two out of six, so I put in the extended firing pin (Cylinder and Slide). Then it went to more like four out of six. The pull weight is currently more than my 10lb gauge will measure, and was a tiny bit over ten pounds before I put in the shim.

 

[RecoilRob]

How far back does the hammer go when firing DA? Have seen people stoning the sear lever that the trigger pushes on to cock the hammer trying to smooth it out...and making it any shorter just reduces the hammer fall. If you have stock hammer spring pressure and it still wants to misfire DA, the hammer might not be cocking far enough. Could just take a new sear lever that's pinned to the hammer to cure it if all else fails.

How is the cylinder timing compared to the DA hammer fall? If it's locking right as the hammer drops it might be short-changing you on the hammer fall. My last three S&W N-frames all locked up well before the hammers dropped in DA and light strikes weren't on the menu at all.

Did anyone ever have problems with the moon clips being too thin? Have you checked the clearance from case to recoil shield just to be sure something doesn't have the cases too far away from the firing pin? Troubleshooting guns is a fun thing...good luck!

 

[straightshooterjake]

AZAndy, glad to hear you are making progress. It sounds like a slightly thicker shim will get the gun working reliably. But it sounds like the trigger will be about 12 lb at that point.

After the gun is working well, you will have to decide if the double action trigger is acceptable to you. If a Smith & Wesson N-frame requires a 12 lb trigger to get 100% ignition, that suggests that something is a little bit out of spec. As described in my article, there are many mechanical issues which can make a revolver require additional mainspring strength. Some of these issues are not too difficult to diagnose and resolve, but others can be quite involved.

45 ACP revolvers generally have the cartridge headspace set by the moon clips, so the moonclips can be a source of ignition problems that would not occur with traditional revolver cartridges.

Please keep us informed on your progress.

 

[MrBorland]

If a Smith & Wesson N-frame requires a 12 lb trigger to get 100% ignition, that suggests that something is a little bit out of spec.

+1. Something ain't right inside, methinks. Sounds to me like you've got a source of excess internal friction somewhere.

 

[L-2]

Do try factory ammo, too. This will rule out one variable and it doesn't matter whether the reloads go off in your other guns, at this time. We're just trying to determine if the gun needs work, first.

Different moon-clips (but what exact brand and thickness is unknown by me) and some factory ammo to debug is my recommendation.

For me, it'd be beyond my understanding if something like a new sear lever needs replacing or fitment, although it sounds like something else to try.

I did some research on moon clips. Brownell's is out of stock for S&W-brand clips.
S&W itself may have them in-stock:
http://store.smith-wesson.com/webap...57842_757839_757837_ProductDisplayErrorView_N