S&W 642 malfunction

[edwardware]

Had an interesting malfunction in my 642 this afternoon at the range. The weapon is probably ~1 year of pocket carry and 100 rounds from it's last complete teardown.

Unloaded, showed clear, reloaded, fired 5, shucked brass, reloaded. . . and the trigger's dead, locked forward. . .


A closer look shows the cylinder center pin stuck forward in the extractor rod. It was barely stuck, and could be pushed back into place with a finger on the exposed end of the extractor rod locking bolt, but would not return home under it's own spring.

A teardown and cleaning reveals the usual pocket woolyboogers, and perhaps the center pin spring installed backward (unwound end on the pin boss instead of the extractor rod end).

It must have picked up a fleck of grit into the pin way in the extractor, and with the spring backwards that was just enough to bind it up. This is surprising, especially after a thorough workout since the last disassembly. I'm certainly glad it happened on a square range.

 

[NMPOPS]

Don't take this wrong, but it sounds more like your fault than the guns. How often do you do a "complete teardown" and why? I have rarely take apart a cylinder and have a few that have never been disassembled with thousands of rounds through them.

 

[edwardware]

Don't take this wrong, but it sounds more like your fault than the guns.

Of course.

The last teardown was a Preventative Maintenance. My pocket carry and IWB holster guns collect lots of fuzz. Every 2ish years max, every one gets PM'd, including complete de-boogering. A range-only or OWB revolver might never need more than wiping out under the extractor.

What's interesting is that the gun ran for ~100+ rounds over a couple range trips, and hundreds of actuations of that center pin (check condition 5 days a week), without a bobble. . . until it didn't. Most failures due to assembly can be expected to show up promptly, but this one was latent.

 

[GRIZ22]

Don't take this wrong, but it sounds more like your fault than the guns. How often do you do a "complete teardown" and why? I have rarely take apart a cylinder and have a few that have never been disassembled with thousands of rounds through them.

I'm with NMPOPS on this. No reason to take a gun completely apart unless it's broken.

If you pocket carry use a pocket holster. More important if you carry dryer lint in your pocket. DeSantis Nemisousworks well, are durable and cheap.

 

[edwardware]

No reason to take a gun completely apart unless it's broken.

Interesting, but I disagree. Perhaps a range-only gun could be treated that way, but a social weapon needs to be inspected completely, and periodically. That disassembly introduces a risk for mis-assembly is no reason to neglect preventative maintenance; if you don't PM, you will experience in-use failures provided you actually use the weapon.

I agree about the pocket holster, and I use one. In my experience, I wouldn't go much longer than 2 years of weekday carry without opening the sideplate to clean. About double the 2-year level of lint is where I'd expect to see malfunctions begin.

Your lint may vary?

 

[red rick]

It sounds like this thread has the wrong title , it should be titled , I Put My 642 Back Together Wrong .

I hope you learned something from your mistake , that could have been a costly mistake on your part .

 

[fastbolt]

...
A teardown and cleaning reveals the usual pocket woolyboogers, and perhaps the center pin spring installed backward (unwound end on the pin boss instead of the extractor rod end).

... and with the spring backwards that was just enough to bind it up. ...

While I'm a longtime S&W revolver shooter (work and personal use), and I went through a S&W revolver armorer class in the mid-2000's (only once, unlike the repeat classes I've done for several makes/models of pistols), I'm curious why your center pin spring was different on each end, with one end "unwound", or why it could be installed "backwards"?

Nothing in the armorer manual indicates the center pin spring is "uni-directional", or has an open (unwound) end. I just checked several spare/repair factory center pin springs which I ordered for my armorer kit after taking the armorer class back then, and all are "closed" at each end (in normal S&W fashion). Ditto the center pin springs I've seen when working on my own J's, and back in the revolver class, and even some removed from a couple older S&W revolvers over time.

Have you modified the factory spring, or used a non-factory spring in your J?

BTW, when armorers are taught to check S&W revolvers during whatever periodic inspections they wish to establish for their purpose, one of the things they're told to look for, to identify possible unauthorized "tinkering", is the presence of a non-factory spring, meaning a spring which doesn't have a closed coil at each end. (The center pin spring ought NOT look like the recoil spring of a 1911, with an "open" coil at one end. )

Also, FWIW, even as a S&W trained revolver armorer, while I check for the normal tightness of the cylinder's extractor and extractor rod, I personally don't disassemble the cylinder's extractor and extractor rod assembly on some frequent basis. Only if it's loosened, or the revolver has been contaminated (submerged in water, etc). It's too easy to risk improperly tightening the extractor and extractor rod (and vigorous over-tightening can cause some problems).

I do check for cylinder freedom of movement (spinning), and for normal lubrication on the bearing points of the yoke periodically, especially with the J's that have aluminum alloy yokes. The stainless and carbon steel yokes seem to retain lubrication (and easy cylinder spin) longer than the alloy yokes used in some of the lighter aluminum & Scandium aluminum framed snubs.

I've had one of our guys who carries a 340PD bring me his gun when the trigger pull got too hard, and he finally had to turn the cylinder by hand during a qual course-of-fire. (That's a hint he'd waited too long to bring it to our attention. ) When I removed the cylinder & yoke to check it, the alloy yoke was both fouled and bone dry. A quick wipe down and a couple drops of CLP to the bearing surfaces restored the little revolver to normal function. The guy was amazed. Since he carried that PD snub as a working secondary weapon (or even as a "primary" during his normal undercover assignment), I showed him how to remove the cylinder and yoke, and check for normal lube on the yoke's front & rear bearing surfaces, and how to be alert to avoiding stripping the SC/AL frame when reinstalling the yoke screw.

I also suggested he remain more alert to any signs of any sort of developing problem with the cylinder spin (becoming sluggish) and the normal trigger pull pressure needed.

 

[GRIZ22]

Interesting, but I disagree. Perhaps a range-only gun could be treated that way, but a social weapon needs to be inspected completely, and periodically. That disassembly introduces a risk for mis-assembly is no reason to neglect preventative maintenance; if you don't PM, you will experience in-use failures provided you actually use the weapon.

I agree about the pocket holster, and I use one. In my experience, I wouldn't go much longer than 2 years of weekday carry without opening the sideplate to clean. About double the 2-year level of lint is where I'd expect to see malfunctions begin.

Your lint may vary?

We can agree to disagree then.

I've carried a gun as a LEO and a civilian just about daily for about 45 years. I'm a firearms instructor and armored for about 43 of those years.

I do remove the cylinder and crane as part of normal cleaning. I've taught others to do this. If you clean and lube properly that negates any need for full disassembly.

I would remove the side plate of a revolver once a year, if all looked okay I'd flush it out with Gunscrubber and lube. No disassembly required.

I have a Commander I still carry on occasion. The only time it's been apart since the factory is after 25 years and maybe 25,000 rds the hammer was dtopping to half cock. Fixed that over 15 years ago and hasn't been apart since.

I carried a M14, M16, M4, M9, Smith M10, and 1911in combat zones and they really got mucked up. Never saw the need to go any further then field strip and flush them out.

Disassembly every two years isn't bad but it isn't needed. I know people who tear a gun down every couple of months and there's no need for that.

 

[edwardware]

While I'm a longtime S&W revolver shooter (work and personal use), and I went through a S&W revolver armorer class in the mid-2000's (only once, unlike the repeat classes I've done for several makes/models of pistols), I'm curious why your center pin spring was different on each end, with one end "unwound", or why it could be installed "backwards"? Nothing in the armorer manual indicates the center pin spring is "uni-directional", or has an open (unwound) end.

I wondered that too, as none of the pictures in Kuhnhausen indicate a directional spring. I believe it the be the factory part, and it definitely has an unwound end. I'm also not sure that it matters; the gun functioned through hundreds of actuations of the center pin with the spring 'backwards'. Maybe it was right all along, and a grain of powder in the pin way is all that happened. I reset it with the unwould end against the Extractor rod end because typically unwound ends bear on ID bosses (ie the rod end) and wound ends bear on OD bosses (the pin boss).

Regarding checking extractor rods, I don't disassemble them until they loosen; every single S&W I own has eventually locked itself up once by backing off the extractor rod (yes, both LH and RH threads) so now they all get threadlocker. When my 642 did that at the range a year ago, I took a hint, did a PM, and gave it a dab of threadlocker. It was reassuringly snug when I disassembled it last week.

 

[fastbolt]

Part # 070630000 $0.51 X CENTER PIN SPRING

If it were a used 642 which someone brought to me for inspection, and I discovered the center pin spring wasn't a design which was closed at each end (like inspecting further if the extractor rod and extractor were already loose), I'd replace the spring with a new factory spring (part # above).

The engineers likely had a reason for having the center pin spring be of the closed coil design at each end. Imagine how easily an "open" end might slip over the pin's middle "boss", potentially binding things at the worst time? I've seen this happen with someone reversed the orientation of a pistol which used a "directional" recoil spring, and it was very difficult to correct at the bench (the gun suddenly became no-op on the firing line).

Also, aside from the risk of the "open" coil end going someplace it ought not go, if someone has clipped the spring, how much has the tension been lessened, compared to a stock spring?

Did you buy this 642 new or used? Just curious.

Oh yeah, I never use threadlocker on the extractor rod threads. (Yoke screw, maybe, as the factory uses it on that one.)

 

[edwardware]

Part # 070630000 $0.51 X CENTER PIN SPRING

Yes, I just added it to my next Brownells resupply. I bought the gun Used Like New, but I do not the believe the former, original, owner did more than fire it 5-10 times.

I never use threadlocker on the extractor rod threads. (Yoke screw, maybe, as the factory uses it on that one.)

Curious, I see this a lot. Why not? Used correctly, threadlocker decreases the necessary assembly and disassembly torque. You don't need to tighten beyond shoulder contact + snug. Without it, you're depending on thread friction to keep the joint tight, despite shock loading and penetrating oil finding its way there. I use a judicious dab of VC-3 all the time, and have never observed a problem during next disassembly (hundreds of gun screws over the years).

 

[fastbolt]

BTW, if the spring has been clipped, I'd be concerned that the tension is now less than what's considered necessary by the engineers in order for the center pin to remain rearward, and able to function as intended, under the sort of adverse conditions as anticipated by the engineers.

 

[243winxb]

pin stuck forward in the extractor

The metal around the pin may flow from hitting the recoil shield , under recoil. This pinches the pin and keeps it from moving to its correct position.

Check the diameter of the hole at its mouth. Open with a drill bit, if needed.

Happened to my s&w m29. Many maximun loads were fired.

https://www.thehighroad.org/index.php?media/s-w-m29-44mag.547/

 

[fastbolt]

Yes, I just added it to my next Brownells resupply. I bought the gun Used Like New, but I do not the believe the former, original, owner did more than fire it 5-10 times.

But did he/she disassemble and tinker with the center pin spring (or anything else)? Did he/she buy it used from yet another previous owner (who might've done the tinkering with the spring)?

Used guns are not only used guns, but might sometimes be "project" guns that someone has tried to "improve" or "modify".

Curious, I see this a lot. Why not? Used correctly, threadlocker decreases the necessary assembly and disassembly torque. You don't need to tighten beyond shoulder contact + snug. Without it, you're depending on thread friction to keep the joint tight, despite shock loading and penetrating oil finding its way there. I use a judicious dab of VC-3 all the time, and have never observed a problem during next disassembly (hundreds of gun screws over the years).

We're not talking about a simple "screw" when it comes to the extractor & extractor rod assembly. There are a couple of springs involved, and their freedom of unimpeded movement and tension is pretty important. Having any threadlocker compound migrate to where it's not intended to be in that assembly could cause the same functioning problems that having any other unintended particulate contaminant might cause, should it find its way inside there. Why add to the possibility?

The engineers have invested decades of R&D and ongoing developmental revisions when it comes to the S&W extractor rod & assembly design and function. If they felt a little dab of threadlocker was a benefit in the extractor rod assembly, they'd have long since been using it (like they do with the sideplate screws).

If penetrating oil is finding its way into your extractor & extractor rod threads, you're probably using too much. (Or applying it in the wrong places.)

 

[243winxb]

a couple drops of CLP

Binds up the cylinder of my 337PD after a while.

The ejectors on my Cirori shotguns acted like the were glued in, after being in storage a few years.

Break Free CLP, not always a good choice. Been using it for years.

 

[edwardware]

Having any threadlocker compound migrate to where it's not intended. . .

and

If penetrating oil is finding its way into your extractor & extractor rod threads, you're probably using too much.

Granted, I don't know that much about tribology, but I can say for a fact that the typical 5 milligram drop of oil (roughly the smallest drop most needle droppers will make) will creep several orders (several tens of times) further than the same drop of open-cured acrylic polymer threadlock.

Why S&W doesn't threadlock at assembly, I can only speculate.

 

[fastbolt]

Binds up the cylinder of my 337PD after a while.

The ejectors on my Cirori shotguns acted like the were glued in, after being in storage a few years.

Break Free CLP, not always a good choice. Been using it for years.

Sorry. I didn't write Break-free CLP as I was using CLP to describe a generic cleaner/lubricant/preservative liquid product. I should've been more clear.

While I'll still use Break-free in a pinch, I much prefer the newer synthetic products that aren't "suspensions" and don't require shaking them to evenly distribute elements of the products. Given my druthers, I also tend to prefer the less toxic or non-toxic products nowadays, when available.

Testing it on a couple of my J's with alloy yokes (M&P 340's), I've found that Liquid Bearings maintains free cylinder movement and spin longer than some of the other lubricants I've acquired at my bench over the years. http://liquidbearings.com/index.php?page_id=4
http://liquidbearings.com/
http://liquidbearings.com/applications.php

Also, cleaning off fouling is more easily and quickly done when I've used liquid bearings, than some other products (both liquids and greases). No smell that I can detect, and it doesn't appear to become "gummy" over time.

 

[fastbolt]

...

Why S&W doesn't threadlock at assembly, I can only speculate.

Never bothered to speculate, myself. I just asked in different armorer classes. While the company will use threadlocker on revolver sideplate screws and rear pistol sight base set screws, they said they didn't use it on the revolver extractor rod and extractor rod assembly to avoid the risk of introducing something that might gum things up and cause functioning problems.

Learning how to properly tighten (not over or under tighten) and periodically check the tightness helps, too.

 

[fastbolt]

Also, to add to what was posted by GRIZ22, as a LE instructor and armorer I've come across far more problems with issued & personally-owned guns where the guns had become rendered problematic due to user/owner "cleaning practices" that were either unnecessarily frequent/excessive, or outright improper, than I have actual "gun problems".

Sometimes it's been the manner of the "cleaning & lubricating", and other times it's been due to a user/owner trying to strip down the gun beyond what was required for normal field-stripping and basic cleaning.

There's usually a reason that LE agencies often have policies which prohibit an issued gun user from acting as his/her own "armorer", or even having an issued weapon serviced or repaired by an outside person (even a gunsmith) without agency approval. Not only is it desirable to avoid risking damage to agency equipment ... but we're also talking about trying to prevent unnecessary risk to the life and safety of the user due to improper/unauthorized "repair/custom work", "modification", etc.

Then again, commercial gunsmiths and factory repair techs/smiths can remain employed by fixing what someone else has already attempted to "fix", even if it wasn't "broken" in the first place. Ditto the people making, and the companies stocking, spare parts.

 

[Jackal]

Its a 642. No disassembly is ever required unless something breaks. Sweaty pocket holsters don't hurt them at all, its what they're made for. My dads J frame and my great grandfathers i frame hand ejector have never been taken apart, ever, and still work exactly like they should.

 

[NMPOPS]

I pocket carry either a 642-1 or a 638-3 daily. I like them both so they are pretty much interchangable. Both were bought new and as stated above I also remove the cylinder & crane for cleaning as it keeps cleaning fluids off the frame. Both had the side plate removed at about 200 rounds to flush and check wear marks and see if anything needed to be done to smooth things out. Since then, both have well over a thousand rounds of reloads through them and I have never removed the side plate on the 642 again. The 638 does get the side plate removed yearly as it is much more prone to dust bunnies. But disassembly--no.

 

[Zaydok Allen]

I guess I'm going to pile on here also and just state that I don't think disassembly of a carry revolver is necessary all that often, if ever. I pocket carried a 642 for two summers. I did a basic cleaning and oiling every few months and whenever I shot it, and it was fine.

Maybe if you carry one for years and years, tearing it apart after for or five years would be warranted, but if the cylinder moves freely, I don't see that it's needed.