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Old August 10, 2002, 09:47 PM   #1
Poodleshooter
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S&W 6906 reliabilty problem-need advice

I am currently the caretaker of my mother's 6906 until the state of NY deems her worthy to take possession of her personal property.
Meanwhile, I am trying to eliminate some nagging reliability problems, namely the following.
1. The weapon fails to go completely into battery about 10-20% of the time. It seems to be hanging up on something on the frame. I've examined the frame and concluded that it could be (from left to right, pistol facing away as if shooting) the ejector/magazine safety, the small black plunger (part of the safety disconnect from what I can tell), the sear (or some part that acts from the rotation of the decocker), and whatever the metal part to the right of the sear is. It hangs up about 1/8" out of battery, and only does so during firing cycles. I can't seem to simulate this by manually cycling the weapon. Manually moving the slide on the frame rails (sans barrel/spring group) does seem to generate a lot of drag, both from the rails and the action components-especially the ejector. As the slide rides over the ejector it gets very stiff and requires some force,as the ejector isn't quite flush when it is depressed.
2. Extraction is fine (seems like the claw might actually be little tight), but the weapon ejects very erratically, sometimes flinging cases at my head, sometimes ejecting normally but always rather weakly compared to my Glock and other auto's I've shot. None of this is as the result of different grips. Deliberate limpwristing seems to have no effect, neither does canting the weapon.

I don't even have the manual for this Smith, nor have i ever worked on one. the rather flimsly ejector/mag disconnect is my prime suspect. Can anyone shed some light on what may be the problem.
thanks in advance folks!
If anyone could point out a good diagram or online manual, I would also greatly appreciate that!
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Old August 10, 2002, 10:24 PM   #2
fastbolt
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This needs to be examined by a S&W armorer or gunsmith ... preferably you should have it sent back to S&W for inspection & repair. S&W has a lifetime warranty.

Unfortunately, your description is more guessing and subjective evaluation than objective description ... but that's perfectly normal, and please don't take it as criticism. It's just that these things need to be examined in person to be diagnosed ...

That being said, though ... the spring loaded ejector lever and the magazine disconnect plunger aren't "fragile" parts. In some of the early 3rd generation pistols the ejectors still had the sharp angled cuts on the bottom of the ejector "belly", which sometimes allowed for cracking & breakage. This was changed to a curved design later, which made them ... pardon the expression, just about bullet proof ... If the ejector tip has broken you'd see erratic ejection, and possibly even some failures to eject.

If the spring under the ejector broke ... unlikely, but anything can fail ... and the ejector doesn't immediately spring up when you push down on it ... and/or these's some crap lodged under the ejector which prevents it from being completely depressed, which could cause the not-fully-depressed ejector to rub on the slide, and cause excessive friction and "drag".

In some cases the sear release lever ... the small lever in the frame immediately to the right of the hammer ... may be slightly out of spec ... and this can also rub on the slide and cause friction.

Another problem might be a chipped or broken extractor hook ... or some debris lodged under the extractor. If you look at the bottom of the slide when it's off the pistol you'll see there's a slot milled to the right side of the stripper rail (the lower center part where the rounds in the magazine are pressed up against), which is open to the space behind the extractor. Usually this only collects a mild dusting of carbon, and very, very slowly at that, but sometimes someone might force debris up there unintentionally, like by using one of the pressure cleaners. Sometimes debris forced into little spaces by fluids under force can't run back out, even though the fluids do ...

Is the pistol lubricated properly? These symptom also occur with bone-dry pistols. Proper lubrication of a S&W pistol would include a large drop of oil, spread with your finger all around the outside of the barrel, from just forward of the barrel lug, to the end of the muzzle ... Ditto for the recoil guide rod ... and for the frame rails, before the slide is put on the frame, place a "raindrop" of oil on the verytop/front of each rail, so it runs on the top of the rail, and over onto the side of the rail (not in the "groove" under the top of the rail, it'll get there on its own after the pistol is reassmbled). After the slide is reinstalled on the frame, and the slide stop reinstalled, manually cycle the slide a few times and you should see some oil start to ooze out the back of each frame rail at the rear of the slide ... The pistol is now lubricated. Oil anywhere else merely is excessive, and might even gather crud that could interfere with the operation. (There's an exception to this routine, but it's only to add a drop of oil to the front of the barrel hood, just where it meets the front of the ejection port, and you can either do it, or not).

Manuals may be downloaded from the S&W website for your pistol.

Of course, there could be other reasons for the problems you're experiencing ... related to either the pistol and/or the magazine ... which is why you should call S&W Customer Service and arrange to have them send you a pre-paid FedEx box so it can be sent back to the factory for repair.

I wouldn't shoot it again until it's inspected and repaired ...

I've fired thousands and thousands of rounds through 6906 pistols, by the way, and aside from actually wearing out a trigger play spring and a sear release lever from a lot of shooting ... they've fed, chambered and fired so reliably it's both reassuring ... one of my duty pistols ... and boring.
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Old August 10, 2002, 11:10 PM   #3
Poodleshooter
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No offense taken! My knowledge is mostly of revolvers and striker fired pistols, not DA/SAs, and my knowledge of Smith autos is next to nil. Your input has allowed me to rule out some issues. The ejector is still under spring pressure (a fairly light spring), and there is no sign of any breakage. There is however a slight feeling of an obstruction as I move the ejector all the way flush with the frame, almost as if a small burr was delaying it's movement downward. I'll clean it out and re-examine. The magazine seems to not be the problem, as this apparently occurs with 3 different mags. However,since the magazine feed lips limit the downward travel of the ejector, would a magazine that was too high or had feed lips that had spread excessively cause the ejector to rise high enough to drag on the slide? Hmmm......
I'm betting that part of this will be cleared up by a good cleaning and oiling, and possibly some polishing of the frame rails. They seem to be rather rough.
Any other input would be welcome.
thanks
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Old August 11, 2002, 12:47 AM   #4
fastbolt
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Do NOT polish the frame rails!

This isn't a steel framed Colt "O" model .45 pistol.

You don't polish frame rails on aluminum pistol frames anymore than you polish the top strap of a magnum revolver just because it's experienced flame cutting. Hmmm, not the best of analogies, but you get the idea

Aluminum has an anodized surface hardening, and while normal wear is to be expected resulting from shooting ... it soon reaches a point where it stops and doesn't get any worse. Unless you fail to properly lubricate the pistol, which can lead to "rough" feeling rails. But don't rely on eyeballing the rails to determine if they're "rough", as normal wear may appear "rough" to someone unfamiliar with aluminum framed pistols.

Polishing the frame rails can easily damage the frame in a way it wouldn't normally be subjected to wear during shooting, and that could cause problems, up to and including rendering the pistol unsafe to fire, and requiring replacement of the frame if the wear reaches a critical point. Leave such things to those who specialize in frame modifications & refinishing for custom pistols.

The magazine lip on the left side is supposed to touch the ejector. Look at the bottom of the ejector and you'll see a small "wiggly" section. That widens the ejector to enable it to be easily pushed against by the magazine lip. It's pushed upward against the nylon plunger, when the slide is closed, to disengage the magazine disconnect.

And yes, it's theoretically possible for an ejector, especially one produced before the CNC machining came into wide use, to be slightly out of tolerance in one pistol ... but possibly not many others ... and stick up just too high out of the frame. This can be corrected by simply replacing the ejector. Tolerance stack-up and variance being what it is, the ejector might work perfectly well in another pistol, so it's easier on the parts just to switch the offending one out and replace it with another.

The small spring below the ejector is the same as that beneath the sear release lever and the firing pin safety lever on the right side of the hammer. It's light, but more than strong enough to do what is required. The only reason I've ever seen one replaced is because it ran away during a detailed disassembly.

The ejector also pushes downward against a "wing" of the disconnector, which in turn pushes downward on the drawbar. These are things that should be inspected by someone intimately familiar with the weapon if there's anything out of the ordinary experienced.

If the pistol still exhibits any of the symptoms you've described after a good cleaning and lubricating, while manipulating it by hand, I'd still recommend having it inspected by an armorer, gunsmith or the factory (in reverse order). Hey, I'd still recommend it regardless ... It's just so much easier for S&W Customer Service to inspect the whole pistol, replace anything that's required, and then give it a proper cleaning and lubrication for you. At least consider calling them and asking about it ... 1-800-331-0852 (if I remember correctly).
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Old August 11, 2002, 08:08 AM   #5
juliet charley
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I would second the cleaning and lubrication.

Also, you did not say what ammo you are using. If reloads, factory or otherwise or just poor quality factory ammo, it could be poorly sized. I would buy a fresh box of good quality 124-grain FMJs and see if that helped (after I cleaned and lulbricated the pistol).
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Old August 11, 2002, 08:54 AM   #6
Eric Larsen
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I had a CZ Compact that started to give me FTF after about 500-700 rnds. I eventually replace the recoil spring with a 20# unit, polished the bottom of my slide (NOT THE RAILS!) and rebuilt my mags a dozen time...nothing helped and it actually got worse.
My locking lug on my barrel was developing a burr on the front corner....it didnt have a factory chamfer on it , anyway the burr was caused from the lug/groove interference during normal cycling of the gun. The burr had enough height that eventually it was causing too much friction between the barrel/slide for the rails/springs to overcome. I had the burr removed and a chamfer put on where it should have been to start with and my gun was 100% after this....CZUSA had never heard of this problem. Many people said "Ohmygod, the barrel must be soft, dont shoot it! But the barrel tested within Rockwell specs....it just didnt have the chamfer as the gun needed for the design and operation. Thought it was worth mentioning....sounds like a possibility for your friction.
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Old August 12, 2002, 09:37 PM   #7
Hellequin
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on this particular gun I´ve had the same problems...with the slide failing to lock....you may also have noted that when you withdraw the magazine the top round tends to jam it or simply falls free...as if it has been pushed out of the magazine.

The problem in mine was that the botttom of the slide that contacts de top bullet on the magazine as the slide cycles brings the bullet forward just to the point to cause a Double feed....polishing that particular part of the gun slide with a 600 sand paper did the trick on my 6906....


no more troubles.....hope I can help.
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Old August 13, 2002, 12:18 AM   #8
fastbolt
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Just a couple thoughts ...

The bottom of the slide which rides through the top of the magazine lips is often referred to as the "stripper rail", because it strips the next round from the magazine. If there's a burr on it, or the bottom surface is too roughly machined (not uncommon in the 2nd gen pistols, and the first few years of the 3rd gen, as well), it can cause increased friction and drag on the next round up as the slide is going into battery. This can cause cycling problems. Not often, but it's possible ... An armorer or gunsmith can easily stone this bottom surface (within a certain safe tolerance) with the appropriate size stone, to avoid hitting and damaging anything else.

On the other hand, I've watched a lot of folks chamber their rounds manually, and do it contrary to how the pistol is designed to operate ... They manually cycle the slide, slowing it with their hands, and "ease" the round into the chamber ... almost as if they're afraid of startling the round ...

The feeding/chambering part of the cycle of operation is designed to be done at a certain speed, and that speed is controlled by the rate of the recoil spring decompressing. In other words, it's supposed to be done at the speed of the counter-recoil movement of the slide. The recoil spring should be doing all the work. Doing it any slower than that can interfere with the mechanical operation.

The round has to be released by the magazine lips at exactly the correct time to slide up the breech face, cam the extractor outward, be sufficiently aligned in the chamber as the barrel is being raised to go into battery, and complete it's upward movement along the breech face as slide and barrel go into battery. That's rough, and leaves a few things unsaid, but it's close enough to give you an idea of the mechanical operations occuring.

If you try and ease the slide forward you can interfere with a few of these critically timed occurrences ...

... The magazine spring may have extra time, before the breech face arrives at the proper speed, to let the round "jump" up a little. This might cause the case rim of the round to miss being guided under the extractor hook properly.

... The movement of the round up the breech face may be slowed just a little, and the movement of the extractor delayed, which can often cause the timing to be off sufficiently to stop the pistol from going into battery. You induced a shooter caused feeding malfunction ...

... Also, the friction of the slide traveling along the top of the next round in the magazine is increased at slower speeds, and this increased friction can dislodge the "new" top round. This often won't become a problem, because the recoiling movement of the slide will move the round backward as the slide travels to the rear under recoil ... mostly ...

Or, you'll remove the magazine, to replace the round you just chambered, and that "new" top round will be so lightly held by the lips, because it's sticking forward a little too far, that when the round catches on part of the pistol frame outside the magazine, the round will then often be dislodged and fall out ... puzzling and annoying you.

There are other factors at work here, affecting these things, but that's the basic idea ...

Feeding & chambering should be done by the recoil spring. Don't try and guide it or "help" it ...

Manual operation during a specific drill ... say, the Tap-Rack-Bang, or Tap/Rack/Assess/Bang ... or whatever you like to call it ... can also cause the same shooter induced feeding malfunction. I've watched happen to shooters during qualifications too many times. No matter which method of manual manipulation of the slide you prefer ... sling-shot or palm-over-rear-of-slide ... make sure you pull the slide to its rearward limit of travel and then release it. Don't allow your hand to remain in contact and slow the slide's forward acceleration. This is asking for a feeding malfunction.

An interesting note not involved in this thread, but related to what I've written ... is how some shooters have created the described "second round" feeding malfunction by doing a "press check". They retract the slide too far ... and since it's moving slowly, there's increased drag on the top round in the magazine ... and the slow return of the slide to battery dislodges the top round forward a little. if the top round is moved too far forward, you may experience a feeding malfunction where the round "jumps" ahead of the extractor, and "jams" at an angle upward against the inside of the chamber, up against the roof of the chamber.

I watched this happen to one guy twice in a single qualification, and I knew it was going to happen each time before it happend ... due to the exaggerated slowness of the slide movement and the length of the movement when he retracted the slide rearward to look into the chamber.

Just because you're doing something you're been taught, doesn't mean you're doing it right ... or, that it should be done each and every time in each and every circumstance.

Sorry ... definitely don't mean to sound like I'm lecturing
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Old August 15, 2002, 10:50 PM   #9
smittty
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Poodleshooter,

I am a S&W armorer and am in the Roanoke area. I've been away from the 'puter since the birth of my daughter on 8-7-02. Trying to keep her rocked to sleep right now. If you haven't sent the gun anywhere and still have the problems, email me at twoofsmith@rbnet.com and we'll go from there.
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Old August 16, 2002, 12:47 AM   #10
fastbolt
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Smittty's reply to Poodleshooter's thread is an example of what makes this board a great place to ask for help ... Sometime's help is a lot closer than you'd think ...

Poodleshooter, I have little doubt that smittty, as a S&W armorer, can resolve your problem

Smittty, congrats to you and your wife on the birth of your daughter ...
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