I fired my new S&W 620 for the second time today and had two “malfunctions”. I’m mystified and, because this is a defensive handgun, I am pretty concerned.

Here’s what happened.

Malfunction1)

I was shooting .38 reloads purchased at the range. After about 50 rounds, while shooting a string of DA slow fire, the gun failed to cycle when I pulled the trigger. When I pulled the trigger, the cylinder rotated part way, then stopped dead. It wouldn’t move forward to lock in the firing position. I swung open the cylinder, inspected it briefly, then closed it and tried again in DA. The gun cycled and fired without incident.

Malfunction 2)

After about 25 more rounds of .38 reloads, the same thing happened – the gun would not cycle during DA. I used my free hand to rotate the cylinder backward (clockwise), and tried pulling the trigger again. Same thing – the cylinder rotated part of the way, then refused to move into firing position. I did this several times – same result.

The cylinder opened pretty easily, and I empted the gun to inspected the bullets. Upon inspections, all the bullets were firmly and uniformly seated in the brass, so t wasn’t a loose bullet hitting the forcing cone. I reloaded the rounds and the gun functioned properly. I realized afterwards I should have inspected the hand and the cylinder locking slots, but I didn't think of it at the time.

I finished off the session with 50 rounds of 158 grain .357 JHP. The gun performed fine, although there seemed to be a fair bit of flash from the front of the cylinder.

This is a brand new gun that I’ve owned for one week. So far it’s had about 200 rounds of .38 special FMJ reloads through it, and about 100 rounds of .357 JHP. The gun was clean when I started shooting today. I cleaned it again this evening, and it looks fine and cycles perfectly.

What the heck happened to my gun? Did it get some powder debris in the action? Is this normal? I’m a rookie when it comes to wheel guns, and I’ve never heard of this. I though revolvers where supposed to be more reliable, and less sensitive to ammo problems. Can anyone tell me what is going on with my gun? Any advice or guidance would be much appreciated.

High primers on the "house reloads" is my guess? Or some powder/lube slag being ejected that may have come to rest in the ratchet or hand's window? The fact that the symptom did NOT reappear when firing the much hotter but "factory" ammo, would tend to support the theory of dubious quality reloads. There's a saying, "you never want to share underwear or reloads with anyone". Unless they're mine, I'm always nervous about them.

+1 I agree

I think it's ****** reloads too, but to test your hand spring, Unload your gun, point it at the ceiling and dry fire it some. If it cycles every time you squeeze the trigger your gun is fine. If not, your handspring needs attention.

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NRA Benefactor Member

Also check the ejector rod for tightness, my 629 ejector rod will work it self loose and that causes trouble with the cylinder moving.

If I don't load em ( Or know who did VERY well) I won't shoot em in my gun.

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Sceva
OGCA SWCA NRA

Agree with all of the above. Double check that ejector rod.

+1000.Shoot factory ammo only.

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WALSTIB

I agree with the high primers, check your primers.

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May God Bless The USA

I had a close call with reloads that came with my 686. I was told by several member not to shot reloads that were not mine and I didn't listen. I nearly blew up my gun and maybe my hand or worse.

Check under the ejector star when this happens. There could possibly be a piece of powder residue which will raise up the star and round which will drag on the recoil shield. If the reloads were with coarse powder such as Unique, it is possible to cause the gun to stop.

Does this model have an Internal Lock? I am unfamiliar with them as I don't own any with the IL, but could this be a possible cause?

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H Richard
SWCA1967 SWHF244

Although I agree with everything the other posters have said, I'd add that, occasionally, even factory rounds can be defective. I've had the same thing happen once or twice firing factory ammo through my 686. And, since I've put about 5,000 rounds through that gun, my guess is that 4998/5000 without incident is that it's pretty good evidence that it was the bullets and not the gun that caused the drag.

I had a (neighbor's hand load) problem when I shot my 642 for the first time several years ago. Learned my lesson...only use the best ammo now in all of my firearms!

Check you B/C gap. If it is a little snug, with lead reloads sometimes just a little fowling on the face of the cylinder will tie up the cylinder. Just opening it sometimes cleans enough off to cycle again.

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Richard Gillespie
FBINA 102

This could very well be your problem. The B/C gap on my 620 is right at 0.005 inch when checked with a shim. At about 120 rounds downrange the carbon fouling on the front of the cylinder can build up enough to cause it to start binding when I am shooting 38 spl. BTW, that is with Federal LE TMJ or American Eagle FMJ, both of which are pretty clean. With a "who knows what" reload I would think it's quite possible that the carbon fouling could build up much quicker. When that happens I either clean the face of the cylinder with a lead away cleaning cloth or run 2 cylinder loads of full power 357 Magnums through it because I've found that full power Magnums are pretty effective at knocking the crud loose and an eye opener to boot.

PS, if your shooting full power Magnums at an indoor range don't be too alarmed if you get hit with some debris once in a while. The indoor range that is most convenient for me is only 60 feet and on 3 occasions I've been hit by jacket fragments. Twice in the face and it wasn't hard enough to draw blood or leave a mark. The first time it happened freaked me out a bit because I was afraid I had a timing issue. Myself and the RO spent a good bit of time looking the gun over for any evidence of shaved brass and found nothing. Last Wednesday at the range I got hit again, right smack in the middle of my belly. Since I was bellied up to the shooting bench when it happened, it was without any doubt debris that was thrown back to the firing line from the bullet trap. Consider this a heads up, make darn sure your wearing your eye protection when shooting the hot stuff, it's energetic enough to throw stuff from the traps a lot further and harder than you might expect.

I'll echo the high primer group. However, I have a 629 that has such tight tolerance that when it was new just the grit from shooting caused it to tighten up and with a cleaning it was ok again. Now that I've put a few rounds through it, it has this problem less. I've also experienced with the 629 a grit under the star ejector causing it to tighten up. Clean it out and back to shooting. You say your 620 is for self defense. Keep it clean, with commercial ammo and you shouldn't have any problem. If you do S&W will check it out for free, I think.

Many thanks for the feedback folks.

I've been looking at the gun and trying to visualize how a primer could interfer with cycling. Does a "high primer" protrude further than it should, and then get stuck on the recoil shield?

I've also been examining the cylinder gap. I can't find my feeler gauges, but it sure does look tight. I'll pick up some gauges and measure it soon.

Based on the info provided so far, I have a gut feeling its the cylinder gap becoming fouled. Like I said, I don't know much about revolvers, but the gun seemed abnormally dirty after only 50 rounds of the cheap reloads.

Both of the times it failed to cycle, I swung open the cylinder, checked for the ammo, then resumed firing with the very same rounds. I believe the simple act of swinging open the cylinder cleared the fouling sufficiently for the gun to work again.

In the meantime, my faith in the gun as a defensive tool has been at least partly restored. I'll put some more rounds thru it and keep an eye on the cylinder gap and primers.

Thanks for the help.

Groo here
Unless your experiencesed " Dun that ALOTT" reloader,and it is ok
in your area "Reloads are for Practice-Factory are for Fighten".
If it is ok with factory -your good to go.

Lead 38s will foul your .357 magnum faster than anything else. The extra gap caused by the short case promotes more leading in the cylinder and forcing cone. Your symptoms do sound like either high primers or excess fouling. Next time it happens, remove the round and see if the primer stands out above the brass. It should be flush or below.
I have a 620 myself and have shot only .357 handloads with no malfunctions. Evenly split between lead and jacketed.

Good info folks. I'm heading to the range this weekend so I'll keep an eye on fouling and primers.

Yep. Groo. I'm agreement. Mas Ayoob has addressed that issue too. He flatly states that factory ammo is the way to go for defensive use, for legal reasons as well as performance.

A fast way to check for high primers is to stand the ammo on a piece of glass ( I use a hand mirror). If it has a high primer the ammo will "wobble" and not stand stright.

Old school method!

Doc

The bad news is I had another malfunction. The good news is that I think the problem has been isolated.

I put another 150 rounds through the M620 on the weekend. All rounds were FMJ .38 special. (For some reason, that range doesn't allow magnum rounds on the steel targets).

After about 90 rounds the cylinder locked up again. After a couple of unsuccessful attempts, I open the cylinder and examined the gun and ammo thoroughly. Everything looked good - no crud under the ejector star, no fouling of the hand, and no high primers. However, the forcing cone area was a mess - heavily fouled. So was the front of the cylinder. Both areas showed a visible "swipe mark", formed by opening the cylinder.

I used a rag to clean the front of the cylinder and forcing cone area, reloaded the same ammo, and proceeded without incident. The gun performed flawlessly for the remainder of the session.

I haven't purchased feeler gauges yet, but I'm pretty sure the problem is a tight gap between the forcing cone and cylinder face. I figure I can either send it to factory, or just remember to wipe it off every 50 rounds or so. I like the way it shoots, so I'll probably choose the later.

I just identified another problem -- the gun is slightly out of time. It is not locking up on every cylinder before the hammer falls. I didn't notice this before. Either I missed it on my ealier checks (after all, this is my first revolver in about 15 years), or it is a new development.

I'm disapointed. This is a new gun, and a fairly pricy one compared to the combat tupperware I'm used to.

I think I'd better call S&W. Any other advice folks?

The gun failed to cycle again on Friday. Because of the failures, and the timing issue, its going back to S&W under warranty.

What you have said makes sense.
If she's a bit out of time and shaving material off of the bullets, that slag along with the normally generated firing dirt has to go somewhere? The forcing cone and cylinder face area's are the first two spots that might logically get hit with it? You may want to take a "read" on the clearance of the forcing cone/cylinder gap pre & post warranty work though, just out of curiosity?
Question, did the area between the forcing cone and the top strap get packed with crud during range sessions? Was it difficult to dig out?