S&W 500 Light primer strike?

[Cheesemaker]

Strange thing today, I fired 30 rounds thru my S&W 500 8&3/8" -
First 5 - all single action - no issue
Second 5 - 1st round SA, fine , 2nd DA - light primer hit (failure to fire), I check wait a few seconds, check the chamber (see pic, top case) -subsequent DA pulls fire fine.
Next 5 (11-15) - all SA - no issue
Next 5 (16-20) - 1st round SA, fine, 2nd DA - light primer hit (failure to fire), I check wait a few seconds, check the chamber (see pic (same story)) -subsequent DA pulls fire fine.
Next 5 (21-25) - 1st round SA, 2nd DA - light primer hit (failure to fire), I check wait a few seconds, check the chamber (see pic (same story)) -subsequent DA pulls fire fine.
Next 5 (26-30) - all SA, no issue.

In summary, all DA pulls right after a SA firing were light on primer strike.
Other DA pulls worked fine.

These were reloads - Hornady & Starline brass, Winchester Large Rifle primers, 34gr Accurate #9, Sierra 350gr JHP.

WLR primers are that hard? Any thoughts?

 

[Walkalong]

Assuming no light strikes that are the fault of the gun, my best guess is the primers were not fully seated.

 

[MEHavey]

Pull the grips and see if the strain screw (near bottom of trigger-guard side of the butt) is snugged all the way up tight.

 

[Cheesemaker]

Good point Walkalong - (as usual). That maybe the case - I still use my (old) Lee hand priming tool (round plate, holds about 100 primers, different seater for small and large primers).

My biggest "concern" is the consistency with the light strikes after the 1st round is fired - and firing DA. I have fired about 200 rounds thru this with no issues - all SA though. Today was the first DA "workout".
I did run about 72 rounds thru my Ruger SRH 44 Mag today too, same drill - 1 SA 5 DA - all worked fine. Primed on the same Lee tool with WLP or CCI#300 primers - no issues there.

Thanks ME - I will check that too.

Appreciate the input.

 

[cfullgraf]

Since it seems the problem occurs only on the 500 S&W Mag, and only when firing double action, I'd suspect a gun problem. Something with the double action mode, maybe the hammer block not getting fully out of the way.

If the miss fires happened randomly in double action mode, I would suspect an ammunition problem. But, the miss fires seemed to be repeatable regardless of the ammunition indicating a gun problem.

Will the light strike ammunition fire when tried under single action mode? Maybe I miss that in the above posts.

MEHarvey's suggestion is something to look at. The screw may have backed out a little.

 

[straightshooterjake]

As you are probably aware, the hammer strike is weaker in double action than in single action. The hammer does not come back quite as far during the double action stroke, and that causes a noticeable difference in striking force. It is not uncommon to find that a revolver which is 100% reliable in single action has occasional light strikes in double action.

I suspect it is coincidence that all the misfires occurred after a single action shot. Certainly, no good explanation for this behavior comes to mind.

Earlier suggestions about the strain screw and possible issues with primers not being fully seated are both good ideas. These are two common causes of problems.

I also want to mention one issue about examining primer strikes. When the round ignites, the primer strike will always look good. This effect happens because when the round ignites, the case and the primer are pressed back against the firing pin with thousands of PSI of pressure. The rounds that do not go off provide a more realistic idea of what the primer strikes really look like.

If necessary, you can increase the strength of the hammer strike by putting the cleaned out shell of a spent small primer on the end of the strain screw to act as a shim. This shim effectively makes the strain screw longer.

If you want much more information about the causes of light strikes in S&W revolvers, I wrote a long article about S&W trigger jobs. The article has a section on the causes of light strikes and also covers all the points I have mentioned here in greater detail.

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

 

[ArchAngelCD]

Did you try to duplicate the failure with factory ammo? Did you try a second strike on the light strike rounds?

It is not uncommon to find that a revolver which is 100% reliable in single action has occasional light strikes in double action.

I'm sorry but that is just not true. I have never owned or fired an unmodified DA revolver that was not 100% reliable without something being wrong with the revolver. If it were true no one could carry a revolver for SD.

If necessary, you can increase the strength of the hammer strike by putting the cleaned out shell of a spent small primer on the end of the strain screw to act as a shim. This shim effectively makes the strain screw longer.

There should be no reason to do a bubba repair on a fine revolver like the S&W 500. If it's broken fix it correctly or send it back to S&W.

 

[ReloaderFred]

If the primers detonate on the second strike, it's a primer seating problem. The first strike finishes seating the primer, and the second strike sets it off.

Primers have to be seated all the way to set the anvil into the primer pellet. That means they have to be seated below flush with the base of the case. My goal is .004" below flush with all primers.

Hope this helps.

Fred

 

[Cheesemaker]

Great info - thank you all.
The rounds did fire on the second attempt. I have never had the issue with single action - only double.
I will check the strain screw and pay more attention when seating primers for my next batch of reloads. I still have 10 rounds from this batch I will take a look at them and pay close attention for any misfire pattern when I use them.

Thanks again.

 

[MEHavey]

You will find that a backed-out strain screw causes an
incredible number of S&W "light-strike" complaints.

Check/screw it tight at your first opportunity.

 

[AABEN]

If it is the screw put some nail polish on it so it will not happen again. good luck

 

[captain awesome]

one of mine did the same thing for a long time, (started out only fireing one out of 5...a terrible record). It turned out to be a variety of problems, some I was able to fix my self some not, but here they are.
first, the strain screw was tight but not as long as my other 500 mags. I took it out to compare. It looked like someone filed it down at the factory. Perhaps that was part of the performance center "action job". I replaced it, things improved slightly.
second, the hammer spring was weaker than other the Smiths and again looked like it had been sanded thin. I replaced it, again things improved slightly. at this point half my primers were being set off.
third, I took the gun apart, and found metal shavings in the firing pin hole. I removed them and polished the firing pin. this made it so it was firing 9 out of ten on average...much better but not good enough.

I also noticed some marks on the hammer. It turned out it was hitting the left side of the frame. I sent it to smith and wesson. they said they "repaired the yoke" but did not replace the hammer...which I thought they should have done. but now it fires 100%.

 

[Walkalong]

You will find that a backed-out strain screw causes an
incredible number of S&W "light-strike" complaints.

Check/screw it tight at your first opportunity.

Or, if not purchased new, someone may have filed it shorter.

 

[Cheesemaker]

I did buy this new. But will check - Thanks again.

 

[Walkalong]

I did buy this new.

Then just check to make sure it is still tight. (Turned all the way in.)

 

[GooseGestapo]

Possible but doubtful on the strain screw.
After looking close at your pic, I think you need to focus on the primer seating.
They appear to be fully seated, but not lightly compressed as necessary to “sensitize” the primer.
In order to allow safer shipping/storage, the primers are assembled such that the anvils aren’t fully compressed against the foil layer over the fuel pellet.

An important aspect of the Lee tool is that it allows you to “feel” the primer seating process. I’ve used them extensively over the past 48yrs I’ve been reloading. You need to feel a slight compression after the primer “bottoms out”, to fully sensitize or “activate” the primer as I’ve heard it described. You’ll notice that the primer surface will be slightly more “flattened” than yours are in the picture.

Another solution is to use Federal primers. They’re the most sensitive of the available primers.
All my competition revolvers have actions tuned to be 100% reliable with Federals. Use of a Winchester is usually ok, and CCI’s likely to missfire unless I tighten the strain screw.

And; yeah, Winchester rifle primers of late are “harder” than they used to be. During the Obama Ammogeddon, Winchester cranked out a bunch of defective primers. They “cheapened” their primers first by elimination of the nickel plating they formerly had, and didn’t make allowances for the weaker cups. I’ve got three bolt action rifles that have pits burned into the bolt faces from the primers blowing out at the radiused edge of the cups. I also suffered a slam fire with a CMP Special M1 Garand that fortunately only busted the stock, broke the sight windage ring, and buggered the radius on the right locking lug mortise.
I’ll never buy Winchester primers again. It wasn’t just one lot number, but at least three! And one of the affected rifles never shot anything but cast bullet loads with modest loads of #2400 (.303Enfield w/155gr Lee .312”-PTGC over 16-20gr). I understand Winchester had a lot of consumer claims regarding guns damaged...

 

[Walkalong]

Good post.

If you check out a primer before seating you will see that the legs of the anvil stick out of the cup a little. After seating the legs of the anvil should be flush with the cup. Or in other words, seated enough so the cup is pushed down over the anvil so the priming mix is pressed between the two. If the firing pin has to do that part (Finish pushing the cup down over the anvil), they are a lot less likely to go off. Not enough energy left to sharply crush the priming mix between the two.

 

[GooseGestapo]

Not totally unrelated but S&W had issues when developing the .500. I had a chance to shoot one of the prototypes at the NRA PPC Nationals. For a dollar a shot, you could shoot one. On something like a dare, a fellow competitor paid and put me up to shooting it. Due to grips and barrel porting of the “longish” barrel, recoil wasn’t that bad! However, it was enough that Tom Gordon, head armorer at the Performance Ctr who built the gun, said that they had problems with the guns “doubling” due to shooter reflex’s reacting to the recoil. The solution was the five shot cylinder requiring a longer trigger pull cycle due to wider spacing. My first impression on your pictures was that you were getting cylinder advance and a light strike on the next round. One of the other shooters at the demo of the prototype had one. That’s one of the reasons for using Rifle primers in the .500...