S&W Hammer Camming Forward Problem

[unclerandy]

This is my cousin shooting his S&W 586. There is a problem with the trigger/hammer. You can see in the second trigger pull the cylinder turns but the hammer camms forward. I've never seen anything like this before. I shot it also and it happened many times. Neither one of us short stroked it. I even removed my finger completely out of the trigger guard to make sure after every shot and it still did it. The gun has not been modified in any way and only has a couple hundred rounds through it. About 2-3 years old. Does anyone have any ideas on what is wrong?

[ojisan]

Here's how it works inside.

https://imgur.com/pPog6zl?

The sliding block shaped thing at the lower right is the rebound slide.
After the hammer falls, the rebound slide pushes under the hammer and rotates the hammer back a little so the firing pin in the hammer nose does not rest on a primer.
Now on the back of the trigger in the gif is a ledge sticking out that catches on the spring loaded lever in the face of the hammer.
The ledge on the trigger pushing on the bottom of the hammer lever is what pushes the hammer back.

In your gun, when you pull the trigger back, the rebound slide is moving out of the way. Your trigger ledge is not catching on the bottom of the hammer lever, so as the rebound slide goes back the hammer falls all the way.

Your ledge, lever and the spring that pushes the lever out should all be looked at.
It might just be all gunked up in there.

[unclerandy]

Here's how it works inside.

https://imgur.com/pPog6zl?

Your trigger ledge is not catching on the bottom of the hammer lever, so as the rebound slide goes back the hammer falls all the way.

Your ledge, lever and the spring that pushes the lever out should all be looked at.
It might just be all gunked up in there.

falls all the way? Its not just falling as if it slipped off the rebound slide, its actually camming forward under tension.

[pacrat]

falls all the way? Its not just falling as if it slipped off the rebound slide, its actually camming forward under tension.

The "TENSION" you mention is the mainspring nudging the hammer forward to its full forward position.

[mausercat]

This is sometimes what happens when too light a rebound spring is installed onto the rebound block. The trigger is not resetting fully forward. If it did the rebound block would push up the hammer against the force of the hammer spring with a wedge built into it. If you have not changed the rebound spring then it must be gunked up with congealed oil or grease. Take it apart and give it a good cleaning. If you don't want to do that spray some carburetor cleaner using the straw into all of the opening in the revolver. Take off the grips and spray cleaner in from the between the mainspring and the frame in the opening under the grips. I would then oil it up with come CLP or equivalent. I bet that it solves the problem. The other cause could be rust inside the gun if some liquid got into the mechanism.

I have a friend who used "Frog Lube" on his pistols and put them away for a year. After a year that Frog Lube congealed and his 1911 would not work properly until he cleaned it out and his revolvers where doing exactly what your is doing.

[unclerandy]

This is sometimes what happens when too light a rebound spring is installed onto the rebound block. The trigger is not resetting fully forward. If it did the rebound block would push up the hammer against the force of the hammer spring with a wedge built into it. If you have not changed the rebound spring then it must be gunked up with congealed oil or grease. Take it apart and give it a good cleaning. If you don't want to do that spray some carburetor cleaner using the straw into all of the opening in the revolver. Take off the grips and spray cleaner in from the between the mainspring and the frame in the opening under the grips. I would then oil it up with come CLP or equivalent. I bet that it solves the problem. The other cause could be rust inside the gun if some liquid got into the mechanism.

I have a friend who used "Frog Lube" on his pistols and put them away for a year. After a year that Frog Lube congealed and his 1911 would not work properly until he cleaned it out and his revolvers where doing exactly what your is doing.

No parts have been changed. I took it apart and cleaned it thoroughly before shooting yesterday. It wasn't really dirty but over lubed. There was no gunk of any kind in the gun before shooting yesterday and no parts altered in any way.

[JTROKS]

You took it apart as in removed the side plate and all?

[ysr_racer]

[dfletcher]

This is my cousin shooting his S&W 586. There is a problem with the trigger/hammer. You can see in the second trigger pull the cylinder turns but the hammer camms forward. I've never seen anything like this before. I shot it also and it happened many times. Neither one of us short stroked it. I even removed my finger completely out of the trigger guard to make sure after every shot and it still did it. The gun has not been modified in any way and only has a couple hundred rounds through it. About 2-3 years old. Does anyone have any ideas on what is wrong?

This is showing a couple of problems. The hammer not camming back in DA mode and a failure to ignite when the hammer does fall. Each should be pretty easy fixes. But I don't think a weak rebound spring is one of them.

At the risk of skipping over an obvious solution, we'll assume the "short stroking" isn't happening. Although were I to go by the video only I would say that someone who is used to shooting striker fired pistols and paying attention to the "reset" - it's short stroking + a weakened mainspring strike.

Does the same problem occur when thumb cocking the action?

I would focus on the DA sear and spring and the hand spring. Easy to check.

In DA mode with the gun pointed up, pull the trigger DA style. If the DA sear spring or hand spring are not working you should get nothing more than the trigger cycling - no hammer lift, no cylinder turning.

My bet is the DA sear and/or spring.

So far as the gun not going "bang" - it could be timing (caused by the hand spring missing) or the mainspring strain screw.

I do suspect there's a part of the story missing though. Such as the gun being bought used or worked in some way.

[ojisan]

No parts have been changed. I took it apart and cleaned it thoroughly before shooting yesterday. It wasn't really dirty but over lubed. There was no gunk of any kind in the gun before shooting yesterday and no parts altered in any way.

Including the fact that you took it apart and after that you have a problem is really important to know.
If it worked right before you took it apart and cleaned it, then it is not put back together correctly.
It could be a rebound slide issue, but do look carefully at the spring that pushes the DA sear lever outwards from the hammer.
Make sure it is in place pushing the lever forward, not laying sideways stuck between lever and hammer.

[SnWnMe]

The lockwork is laid out so you can clearly see what each part does.

Go back in there and look at the interplay of parts again.

[dfletcher]

Including the fact that you took it apart and after that you have a problem is really important to know.
If it worked right before you took it apart and cleaned it, then it is not put back together correctly.
It could be a rebound slide issue, but do look carefully at the spring that pushes the DA sear lever outwards from the hammer.
Make sure it is in place pushing the lever forward, not laying sideways stuck between lever and hammer.

First time I disassembled a MIM S&W, removed the hand from its trigger, I assumed it and the spring were held in place just as was the machined version. Felt that little "sproing" as I removed the hand from the trigger. Spent hours on the floor looking for the spring - think I found it in a puddle of tears. Then came trying to figure out how the damn then went on to the trigger. Not exactly intuitive.

The DA sear is what I would call a geometric fit, meaning there's nothing really holding it in place other than design - no pins or screws, just dropped in. There's enough slop that if the spring is gone the DA sear will probably drop forward on its own some of the time.

[Featureless]

Revolvers are complicated machines. I have an older 586 that belonged to my father. He shot it frequently and after his death, I discovered its timing was off. I sent it to S&W, they sent me the estimate, and I paid to have it repaired. It now functions flawlessly. Money well spent.

[max21]

The DA sear may not be grabbing the hammer to start it rearward and maybe because of to much oil around and under the DA sear. Try cleaning the action with brake cleaner and put just a drop of oil on each studs.

[unclerandy]

You took it apart as in removed the side plate and all?

Yes