New 686+ mainspring came loose. Strain screw tight

WTH?

New 686+ with under 1k rounds. Got pretty gummed up with lead to the point of it barely working recently. (Cleaned after every trip out)

I clean it up, apply a tiny amount of grease to moving parts, dry fire about ten times before loading and putting into service....and it stops working.

Mainspring had popped out.

Checked strain screw, which I'd loc-tited. It was tight. Loosened it to get spring back in place. Seems fine now.

What the hell happened? I don't trust it now. Spring & screw are factory. I've had zero light strikes.

https://www.youtube.com/watch?v=VmdlOhMWwu0
See ~08:15 minute mark.
I don't know what happened.
I'd double-check to ensure the top of the mainspring isn't somehow broken.
I'd double-check to determine where the top of the mainspring hooks onto the "stirrup" is ok.

Hopefully all relevant parts are unbroken and it was some weird mis-assembly issue.

Here's another video: https://www.youtube.com/watch?v=YPoOqBArPaM&t=271s
Look, starting around 16:25 minutes for perhaps some better video. The talking gets a bit distracting. Turn down the volume which may help.

Quote:

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Originally Posted by L-2

https://www.youtube.com/watch?v=VmdlOhMWwu0
See ~08:15 minute mark.
I don't know what happened.
I'd double-check to ensure the top of the mainspring isn't somehow broken.
I'd double-check to determine where the top of the mainspring hooks onto the "stirrup" is ok.

Hopefully all relevant parts are unbroken and it was some weird mis-assembly issue.

Here's another video: https://www.youtube.com/watch?v=YPoOqBArPaM&t=271s
Look, starting around 16:25 minutes for perhaps some better video. The talking gets a bit distracting. Turn down the volume which may help.

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Thanks. Watched the videos. I might remove the side plate to check for damage or debris.

I'm wondering if it could be related to me pulling the trigger hard when the cylinder face / breach was gummed up with bullet lube / lead.

I think the extra gunk was caused by the double-grease rings of the 187 gr bullets. (Loaded mildly to 900 fps per my chrono with CFE-P)

I opened it up and inspected.

No screws loose, no broken or obviously bent parts.

Chalk it to “anomaly”. Odd shit happens occasionally.
I do know my way around DA Smith Revolvers; but if nothing is broken, everything tight- that shoulda never happened.
You might check to be certain Strain Screw hasn’t been shortened for a lighter, DA trigger pull.
If it has, there isn’t the tension on Main/Leaf Spring, which conceivably cause Mainspring to pop out.

Quote:

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Originally Posted by gaijin

Chalk it to “anomaly”. Odd shit happens occasionally.
I do know my way around DA Smith Revolvers; but if nothing is broken, everything tight- that shoulda never happened.
You might check to be certain Strain Screw hasn’t been shortened for a lighter, DA trigger pull.
If it has, there isn’t the tension on Main/Leaf Spring, which conceivably cause Mainspring to pop out.

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I bought the gun new.

When I removed the mainspring as part of replacing the safety with the Original Prescision button, I made sure to tighten the strain screw very tight, and with Blue Loc-tite.

I've had no light hits, and the first thing I checked was the strain screw by attempting to tighten it. Didn't budge. Then I loosened it and it took considerable effort to defeat the Loctite. With screw nearly out I was able to put the mainspring back in place without removing the side plate.

I removed the mainspring & sidepate last night to inspect everything.

Probably gonna sell it. I lose faith in a gun easily.

I've been dry firing it a bit. Everything feels fine.

Perhaps something shifted when the cylinder was tight because of the lead & grease debris?

I'd have to remove my optic and mount as well as the safety hole plug and stock grip to put it back to stock if S&W would send me a return label.

They'd probably fire it, do a cursory inspection, and send it right back.

At least if my Colt King Cobra breaks I can send it back as-is because it needed nothing changed. Awesome revolver. Well, except for several reports of broken hammers. :(

I'd love to see someone make some milled / forged steel hammers to put in new Colts. I'd do it. Not sure if broken hammers are an Anaconda or Python issue. Could just be Cobras / King Cobras.

I tried to attach an image but it's way to big.

If I shrink it, you won't be able to see the detail.

Looking at pictures on the internet it seems S&W has changed the way the mainspring attaches to the hammer.

I found images of hammers that have a pin retaining a piece that has the pegs the mainspring loops on.

Mine doesn't have that pin. Instead the hammer has a horseshoe shape the piece with pegs, which is also a different design, fits into. There is no pin retaining it.

The hammer isnt broken, it was made this way. I took pics with my phone so I could see fine detail.

I wish I could post pics.

Aha!

Mine is like this.
https://i.ytimg.com/vi/uvRllrPSfHo/maxresdefault.jpg

Not like this, which seems a better design to me.
https://www.schludershots.com/media/...sy_375_low.jpg

Good Lord.
Cost cutting measure allowing elimination of the two parts that used to hold top of mainspring in place.
Hard pass on the MIM “better” crap.

Quote:

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Originally Posted by Ron3

....I was able to put the mainspring back in place without removing the side plate.

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I think this is the source of your disappointment.

If you don't remove the sideplate and Mainspring disengages from the Stirrup, you couldn't visually confirm that the two parts were correctly connected before tensioning the spring again. You were just fishing in there, blind and didn't get the hooks completely onto the stirrup pivot.

I have no interest in a 7-shot but, since its busted, I'll give you a dollar for it. :laugh:

Quote:

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Originally Posted by Wildcat

I think this is the source of your disappointment.

If you don't remove the sideplate and Mainspring disengages from the Stirrup, you couldn't visually confirm that the two parts were correctly connected before tensioning the spring again. You were just fishing in there, blind and didn't get the hooks completely onto the stirrup pivot.

I have no interest in a 7-shot but, since its busted, I'll give you a dollar for it. :laugh:

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The spring never should have popped loose the first time.

I, too, was surprised I got the mainspring set again after removing the strain screw but without removing the side plate. Got lucky I guess. It seemed fine.

Later I decided to do a thorough inspection and removed the side plate, strain screw, and mainspring. Put it back together and again, it seems just fine.

But I don't trust it enough to carry it now and never will.