I have a 5900 series S&W that the hammer follows the slide into battery when the trigger is not squeezed and the magazine release is used. In other words, when the slide is locked back and I release the slide with the magazine release lever, the slide slams forward and the hammer follows it to a decocked position. It will not do this when the trigger is squeezed (Thank God) and the firing pin block is preventing slam fires as a result. I am suspecting its either the sear or the sear spring. Before I put my order in with Numrich for both, is there anything else I should check or order, such as the sear release arm or disconnector?
5900 series hammer issues.
- Thread starter S&W59
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CDKJudoka
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Do you have the safety lever down when you do it? If so, then it is working as it should.
No, safety lever is not engaged.
CDKJudoka
Member
Okay, did you do a complete disassembly? Because it sounds like something is hitting the decocking lever in the frame that is causing it to decock when the slide goes home. Unless you did some work to the sear or sear spring, I find it highly unlikely that they are the culprits.
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You don't mention whether or not you are the original owner, or if you purchased the gun used.
The repair manual indicates a defective sear, sear spring, or hammer may be the cause. If it's not a frame de-cocking lever model and you have not done so, and are familiar with the internals, I would suggest a complete disassembly and thorough cleaning of the frame and internals from stem to stern. Before purchasing new parts, check the integrity of the sear bevel, and the SA hammer notch to verify that they have not been modified and are not damaged. (check them with a magnifier if you have one) Also check the internal springs, especially the mainspring.
While replacement of parts may be necessary to fully repair, the internal cleaning may solve the problem of the hammer following the slide forward if the parts are not severly worn or modified/damaged, and springs have not been changed from the OEM ones. If the internals appear to be in good condition, a new mainspring and/or sear spring may be all that is needed.
The repair manual indicates a defective sear, sear spring, or hammer may be the cause. If it's not a frame de-cocking lever model and you have not done so, and are familiar with the internals, I would suggest a complete disassembly and thorough cleaning of the frame and internals from stem to stern. Before purchasing new parts, check the integrity of the sear bevel, and the SA hammer notch to verify that they have not been modified and are not damaged. (check them with a magnifier if you have one) Also check the internal springs, especially the mainspring.
While replacement of parts may be necessary to fully repair, the internal cleaning may solve the problem of the hammer following the slide forward if the parts are not severly worn or modified/damaged, and springs have not been changed from the OEM ones. If the internals appear to be in good condition, a new mainspring and/or sear spring may be all that is needed.
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Purchased it used. Completely filthy and I did a complete breakdown and cleaning, removing all trigger group and action parts and giving the entire assembly and frame a cleaning with brush and cleaning fluid.
Your comments did make it dawn on me to remove the sear safety release arm temporarily and see if it stops doing it. If so it could be the sear release spring not keeping the sear release arm elevated such that when it slams into battery its triggering the sear release that the safety selector would otherwise activate when depressed. I guess that would be my first point of investigation; the sear safety release arm and spring.
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With the manual safety in the up position, the sear release lever would not cam down when the slide closed, whether the spring was in place or not.
My guess would be the SA sear/hammer interface has been compromised in some way.....either by honest wear or intervention. Perhaps in an attempt to lower the SA trigger pull rate. There is also the possibility that the sear spring has been bent back, for the same reason.
My guess would be the SA sear/hammer interface has been compromised in some way.....either by honest wear or intervention. Perhaps in an attempt to lower the SA trigger pull rate. There is also the possibility that the sear spring has been bent back, for the same reason.
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It appears to be the sear release arm. Removing the safety selector and cycling the action leaves the hammer in the cocked position. Reinstalling the safety selector resumes the issue. I will order a new sear spring, sear arm spring, and sear arm. I will try a fresh set of springs first. If that doesn't correct the issue then I'll shave the sear arm at the top incrementally with the intention of it stopping the hammer following the slide while dropping the hammer when the safety selector is used. I'm of course hoping the new springs will fix this.
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It's possible that the sear release lever in the gun has been replaced and not been properly fit. The sear lever has to be timed properly to the manual safety body so that the hammer falls at the correct time when the manual safety is rotated down. This is done by removal of material from the bottom angled foot on the sear release lever itself, and checking for proper fit and timing with gauges. Proper fitting of the sear release lever is critical to the proper operation of the manual safety.
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The safety selector engages the sear arm and drops the hammer at about just under the half-way mark between 'fire' and 'safe' at rest positions. As such, I am suspecting its an improperly fit sear release arm. I will carefully and incrementally file the bottom angle of the arm and check until the hammer stays cocked but also the safety decock also works. I needed some parts anyway, so this will just round out my order to Numrich. Thanks for your insight.
rosewood
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Why don't you send it to S&W and let them fix it under warranty. Shouldn't cost you a dime but the gas to drive to Fedex. I have recently sent 2 to them to have the trigger play spring replaced and got them back in like 3 weeks.
Rosewood
Rosewood
That is a viable and legitimate course of action to be certain. However, I dislike shipping my firearms. There's something that bothers me since I have had parcels disappear before and some of the items in question are not replaceable. In this matter, its a Lew Horton 5967. I will likely never find another. Secondly, I enjoy diagnosing and fixing firearms. Back in the day when FN-FAL and L1A1 kits were plentiful with military barrels and Imbel receivers cost 75-bucks, I built, headspaced, and barrel indexed my own FAL's. I have several from just about every country in the world that issued them, including Israel. For what someone would have spent on a Springfield Armory semi-auto M14, I could manufacture three FAL's and have the fun of doing it and the personal satisfaction of making drink cans vanish at 150 yards at the range knowing I built this.
rosewood
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I understand. I have built a few 1911s myself, rebarreled a Savage action and generally repair everything I have myself. However, since S&W pays for the parts, I am more than happy to let them do the work. Mine really were not collectors items though.
Good luck,
Rosewood
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From your description, it sounds like the sear release lever is properly adjusted, or "fit" to the manual safety. It's difficult to diagnose however without being able to examine the function first hand.
My gravest concern is the fact the pistol has the hammer following the slide into battery without trigger pull or safety engagement. I would prefer the pistol be 'cocked and locked' like a 1911 than have it do this. The only thing making the pistol slam fire 15 rounds is the firing pin block and I'm putting the well-being of myself and those around me at the range on a tiny piece of metal and a firing pin I pray won't shear. As such, I made an effort to correct the sear arm this morning. I took a bit too much metal off and now the safety engagement makes the pistol 'cocked and locked.' Which I feel vastly more comfortable with. I had some other parts I needed from Numrich so adding two factory-new sear arms wasn't a big deal. If all else fails, I will send it to S&W. But I am now more confident taking the pistol to the range knowing I won't bring harm to others or myself.
JohnHL
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S&W59, in post #6, you said you did a "complete breakdown and cleaning".
Did this hammer following problem exist before you did your "complete breakdown and cleaning"?
John?
Did this hammer following problem exist before you did your "complete breakdown and cleaning"?
John?
The problem occurred before the detail cleaning and persisted after. Its what prompted me to do a full detail cleaning.
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As I indicated in post #5, the repair manual indicates the problem is most likely due to a compromised sear/hammer interface, (bevel/cocking notch) or the sear spring. The sear release lever would not cause the hammer to follow the slide forward with the manual safety in the "up" or "off" position.
If the mainspring (cut or aftermarket) or the sear spring have been tampered with, this could also have an negative effect on the integrity of the hammer/sear with respect to their working together properly.
Also, keep in mind, the sear release lever is not a "drop in" replacement, and must be fit to the gun to work as designed.
If the mainspring (cut or aftermarket) or the sear spring have been tampered with, this could also have an negative effect on the integrity of the hammer/sear with respect to their working together properly.
Also, keep in mind, the sear release lever is not a "drop in" replacement, and must be fit to the gun to work as designed.
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JohnHL
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Excellent!
Next question(s):
Which exact 5900 model is it?
How long have you had it?
Has it had this problem for as long as you have owned it?
Do I understand you correctly in that the hammer following problem does NOT occur when you hold the trigger back?
In other words, in normal operation, when the pistol is fired, the slide will cycle, chamber a round, and go into battery before the trigger is released to its reset, and the hammer will remain cocked in the SA position.
John?
Its a 5967. Had it about a month. The problem existed since I bought it, likely why it was for sale and cheap. The hammer would follow the slide into battery when you either hand-racked the slide or used the slide release. It would not follow into battery with the trigger pulled as there were other elements involved that prevented the sear arm from dropping the hammer. Its a moot point at the moment as the sear arm has been more or less disabled, turning the action into a 1911-style 'cock and lock' safety. The hammer no longer follows the slide because the sear arm no longer is engaging the sear. I have replacement parts inbound and if all else fails, I can send it in to S&W although I loathe to ship my firearms, particularly if they're hard to come by models.
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Since you are unfamiliar with the pistol, including manual safety timing, and proper fitting of the sear release lever, I would suggest contacting Customer Service and sending it back to S&W for an evaluation and repair, or getting in contact with a local S&W armorer if there is one in your area.
Shipping problems notwithstanding, improper fitting of these critical can present real and substantial hazards to you and others.
Shipping problems notwithstanding, improper fitting of these critical can present real and substantial hazards to you and others.
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The replacement parts arrived from Numrich. Its a good thing I ordered two sear arms, as the lessons I learned fitting the first made fitting the second go easier. The pistol now has proper hammer retention and release when the safety is used. It stays locked back when I use the mag release and normal cycling of the pistol. It drops the hammer when the safety is used and keeps the hammer from cocking when the safety is on. It was a little tedious fitting the part, checking function, more fitting, so on and so forth. I could observe during fitting how the arm engaged the sear and at what point it would trigger a hammer drop. I either lucked out or fitting the sear just requires a little common sense and patience.
Anyway, the pistol is now restored, both physically and functionally. The engraved name is gone, the gun is immaculately clean from the complete strip and total cleanup. The springs are replaced with new factory parts, the safety works again as it should, its all working well and looking good. Technically, its the only mid-size 5900 series pistol made and unlike the other Lew Horton models, unique in that regard. It took time, patience, (money), and a desire to make it all right. Turned a mistreated pistol into something I actually value as much as the 1000-series pistols I have and looks nothing like how i found it.
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