Ok, sorry if this has been covered, but the search engine does not like me.

The weapon in question is my 19-3, 4". I have fired about 6 or 7 cylinders out of is so far. My issue is, in that amount of firing I have had 3 light strike type FTF's. After waiting about 30 seconds I open the cylinder and set it up to re-attempt firing that chamber and it then fires fine. When this happens it appears that for some reason the hammer just isn't hitting the primer very hard and leaves a shallow/faint imprint on the primer. When the weapon does successfully fire a round, the dent on the primer is nice and deep and well defined.

I have removed the side-cover and lightly cleaned and lubed the internals. Everything is quite clean inside.

I am thinking maybe try a new mainspring for the 12 bucks they cost?

Anybody have any other thoughts or advice?? Am I on the right track with replacing the mainspring?? I have a bit of doubt as to that being the issue because of the nature of the malfunction...

Thanks

Were you using factory ammo or reloads? If reloads, the cause could be a high primer. If factory ammo, you should check the strain screw to ensure it is tight.

I was using ammo reloaded by an FFL ammo manufacturer. Pardon my ignorance, but would a high primer fire normally on the second attempt?? Or is the light strike happening because the primer isn't all the way seated and the hammer actually drives the primer the rest of the way in, killing the momentum the hammer/firing pin has in the process??

I did forget to mention, the strain screw is tight.. Screwed all the way in.

I did notice though, that my old M19 has a MUCH lighter/smoother DA pull than my 629-6 and 686-6... Is that just the difference between a broke-in old school Smith and a pair of not quite yet broke-in new Smiths? Or could that be indicative of a worn mainspring?

Your evaluation of the primer strike issue is correct.

The first suspects are the primer seating with custom loaded ammo and/or the tightness of the main spring screw. You've checked your screw and it's OK. Other culprits can be powder residue build-up around the hammer and worn or defective firing pins.

I re-load and that quickly teaches the importance of proper primer seating. When that has happened to me I've found the problem has most commonly been primer brand selection or my not completing the proper seating depth. All primers are not alike and some require a slightly heavier pin strike to impact the anvil.

I've discovered the Federal brand is the least prone to a failure to fire (FTF) incident than other brands for me.

Others may disagree but I'd check the issues I mentioned before purchasing a new main spring... Beyond that I'd suggest you have a qualified gunsmith evaluate you situation.

There is nothing more upsetting than to discover ammo or a firearm may malfunction when it's called upon to protect your life someday... You'll get it straightened out...

JMHO

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Terry

It is also possible that the strain screw, although tight, has been shortened - a step some misinformed souls take as part of a
"trigger job". This can be cured by replacement (preferred), or by placing a spent primer between screw and spring.

__________________
Pisgah

my thoughts also.

Someone may have replaced the mainspring with one that provides less tension. That would definitely lighten the trigger stroke but might also produce light strikes. It's not unusal for people to "tune" their revolvers to handle only a certain subset of ammunition -- their own reloads, for example, loaded with Federal primers -- knowing that the result will produce light strikes with factory ammo. Fortunately, there's an easy fix, just replace the mainspring with a slightly more powerful one. You'll find that this makes the double action trigger stroke slightly heavier but it will also guarantee ignition.

Can not use Winchester Fed 150's no problems

Shortening the strain screw is not misguided, unless it has been overdone. This is actually how the factory sets trigger pull. The misguided approach is to instead bend the mainspring hooks backwards.
Placing a spent primer under the strain screw is WAY to much. Usually a 0.005" to 0.008" shim is all that is needed, especially on a gun that already fires most of the time.

Mainspring should fix it. The primer on a fired round is dented more because it moves back under pressure into the fireing pin. Primers give few problems.--JACK

[QUOTE=Dooman;136325579]I was using ammo reloaded by an FFL ammo manufacturer. Pardon my ignorance, but would a high primer fire normally on the second attempt?? Or is the light strike happening because the primer isn't all the way seated and the hammer actually drives the primer the rest of the way in, killing the momentum the hammer/firing pin has in the process??

The first strike typically seats the primer to its full depth and the second one fires it.

Thank you all for taking the time to advise me on this little situation. It sounds like the logical first step for me is to try some descent factory ammo in it and see how things go.

If a box of 50 factory loads all go off without a hitch, I would blame this on primer seating.

If I still experience occasional light strikes with factory ammo, I will then try a new mainspring, likely a Wolf with S&W factory poundage rating.

From there, if the problem still persists, I will look into the mainspring set screw. Is there a measurement so I can put my caliper to it and figure out if it has been shortened or not?

Lastly, someone suggested a worn firing pin, and/or dirty gun in the firing pin area. I also forgot to mention that the gun was spotless clean, inside and out when I had this issue.

So, that leaves the firing pin. How does one check for wear? Or does one just replace it and give it a whirl?

So, does this diagnosis sequence seem about right?

Thanks again for all the advice. Just about all that has been suggested I can do myself. About the only thing I would have a GS take care of is the firing pin replacement.

I would not worry too much about this. High primers are a relatively common problem with reloads and factory ammo should solve the problem. If you still get light strikes, the suggestion of placing a fired primer cup under the strain screw is a good one and will quickly tell you if the mainspring is at fault. I actually have one gun with a fired primer in place as I've been too lazy to replace the mainspring.

Ok GyMac. Thanks for the insight.

I will let you know what ends up being the culprit. But I probably won't be going shooting again for a week or 2..

Hammer mounted firing pins rarely cause problems. If it visually checks out ok, then it is probably the mainspring tension, or primers not fully seated in the cartridge case. Primers should always seated to the bottom of the pocket, otherwise it provides a cushioning effect to the firing pin impact.

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Richard Gillespie
FBINA 102

Gotta say something here....

Before handloading gets a bad wrap as the only culprit causing a FTF it can occur often with factory ammo too. Usually that is the first indication the problem is somehow mechanically related rather than improper primer seating. Primer related FTF tends to be uniquely a re-loaders problem because factory ammo is made from all fresh and new unfired components

Probably the three biggest hand load related issues causing a FTF are, (one), the improper cleaning of residue out of the primer pocket. That buildup prevents the primer from being seated properly and can cushion the first impact of the firing pin against the ignition anvil, as Nightowl mentioned. (Two) The improper adjustment of the priming tool. And (three), oil or moisture invading the primer or pocket.

Many of us know reloading to be a very dependable and effective alternative to the high cost of factory ammo. It is the only way to develop high performance ammo tailored to each individual firearm. Nothing is as easy or uncomplicated as it may seem. The same holds true for reloading.

The person doing the reloading must possess good common sense and be meticulous with the process. Those who don't give the activity an unfair and undeserved image of somehow being inferior or unreliable compared to factory ammo....

Just sayin'..

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Terry

Thanks for the info TDC.

I must ad that I have the utmost in confidence in my reloader. He is an FFL licensed ammo manufacturer and has been doing it successfully for years. One reason I haven't ruled out a mechanical issue is that I have yet to have issues with his reloads with my newer Smiths. This M19 has a noticeably lighter DA pull than my 686-6 and 629-6. But just as part of the process of elimination I will first try a couple of boxes of factory ammo and see how it goes from there. After all the good advice here, I really have no idea what will turn out to be the issue.

My own Model 19-4 suffered from occasional light strikes using factory ammo. Seemed to happen with some brands, and not at all with other brands. It also had a carry up issue.
I took it to gunsmith Andy Horvath, who diagnosed a light mainspring and possibly an over shortened strain screw. Also some end shake.
It is being fixed right now and hopefully will be finished soon.
Can't wait to get it back!

Well, since my last post in this thread, I have fired a few more rounds out of my 19-3.. roughly 50 or so. I had no light strikes. Checking my spent cartridges I see a nice well defined, deep firing pin dent. I think I was experiencing an occasional high primer.

After thinking about it more, I had 2 or 3 light strike misfires with my brand new, unaltered 686 since I bought it in Nov of '10.

Also, I have made mention of the possibility of the occasional high primer to my reloader. I'll have to see how my next batch of rounds perform...