S&W Hammer Camming Forward Problem

[unclerandy]

Interested in finding out what the issue is. Hope you figure it out.

Me to x 2

[unclerandy]

An earlier post stated the gun was taken apart and the DA sear spring was in place, which I interpreted to mean removing the sideplate - what was disassembled, was the sideplate removed?

All that's required to remove that "tension" is backing off the mainspring strain screw. Then remove the grips, remove the sideplate screws and then the sideplate by tapping the frame. To know for certain what is wrong and to fix will require sideplate removal.

The DA sear can be checked for spring tension without removing the sideplate. Cock the hammer and take something thin (like a paperclip) and press down on the DA sear. It's visible through the frame opening between hammer and rear sight. It should move down and back up. If it doesn't, it's because the spring is missing/not functioning. Which, I'm pretty sure, is the problem.

I got it back from him yesterday. I checked the DA sear as you suggested from above with the trigger cocked. It does have tension and doesn't seem to bind at all. I was able to get the issue to repeat and bumping the gun against my hand would get it to "reset".

[unclerandy]

An earlier post stated the gun was taken apart and the DA sear spring was in place, which I interpreted to mean removing the sideplate - what was disassembled, was the sideplate removed?

All that's required to remove that "tension" is backing off the mainspring strain screw. Then remove the grips, remove the sideplate screws and then the sideplate by tapping the frame. To know for certain what is wrong and to fix will require sideplate removal.

The DA sear can be checked for spring tension without removing the sideplate. Cock the hammer and take something thin (like a paperclip) and press down on the DA sear. It's visible through the frame opening between hammer and rear sight. It should move down and back up. If it doesn't, it's because the spring is missing/not functioning. Which, I'm pretty sure, is the problem.

I've been studying the internals now for a couple days. The DA sear is not resetting properly. The spring is in place and properly nested in both the sear and the hammer. So the million dollar question...why would everything work fine for about 400 rounds and then start hanging up. No signs of nicks, burrs, cracks or anything else. The rebound slide nor the rebound spring are an issue because the trigger returns fully forward to metal on metal contact with the frame.

[unclerandy]

[ojisan]

First I want to compliment you on both of the videos that you made.
Both clearly show the problem.
Excellent!


We were all fairly close in the assessment of the problem being the DA sear.

I suggest you remove the sear from the hammer and be sure there is not anything in top area of the sear and where it rides in the hammer that might be gumming up the movement.
I would also carefully inspect the bottom of the DA lever and the trigger ledge for any burrs or damage.
Some very light stoning of those engaging surfaces and edges to smooth the sticky point will probably fix it.

Good luck and keep us posted...it's certainly an odd problem.

[unclerandy]

First I want to compliment you on both of the videos that you made.
Both clearly show the problem.
Excellent!


We were all fairly close in the assessment of the problem being the DA sear.

I suggest you remove the sear from the hammer and be sure there is not anything in top area of the sear and where it rides in the hammer that might be gumming up the movement.
I would also carefully inspect the bottom of the DA lever and the trigger ledge for any burrs or damage.
Some very light stoning of those engaging surfaces and edges to smooth the sticky point will probably fix it.

Good luck and keep us posted...it's certainly an odd problem.

I have inspected these parts by touch and under magnification. No burrs to speak of. I agree that stoning or smoothing will likely correct the issue. What I really want to know is what changed?? 400 rounds no issues. When my cousin first hit me up he sent me a video showing that the hammer would not cock fully in double or single action. After me taking it apart and cleaning things up we took it and shot it. Thats the first slow motion video. So its gone from working fine to not cocking fully to not setting in double action. One would think that the action would become smoother with time not the opposite.......

[ojisan]

I'm wondering if someone short stroked the trigger and then continued to pull really hard, this might have slightly bent or misaligned something.

[JTROKS]

So the DA spring is properly installed?

[ojisan]

I didn't want to mention that again, but it still could be this...either out of place or maybe smushed or bent to one side...if unclerandy removed the sear lever from the hammer and made sure all was correct when reassembling then something has to be misaligned for some reason.

[unclerandy]

So the DA spring is properly installed?

[unclerandy]

My current theory is this; the DA sear has a slightly sharp edge. During the course of 400 or so rounds the sear wore a “shelf” on the trigger engagement surface and it doesn’t want to clear now under the tension of that tiny spring that may or may not be in spec.

[JTROKS]

Take the hammer out. Do this several times, push the DA sear in slowly - will the spring push it back to normal operating position? If not there is binding either with the spring, or the DA sear itself, or a foreign debris in there.

[unclerandy]

Take the hammer out. Do this several times, push the DA sear in slowly - will the spring push it back to normal operating position? If not there is binding either with the spring, or the DA sear itself, or a foreign debris in there.

The sear it self has no hinderance at all with the hammer out of the gun. You can see in the video I posted that the sear does rub against the back of the trigger ledge and has to be nudged forward.

[JTROKS]

The sear it self has no hinderance at all with the hammer out of the gun. You can see in the video I posted that the sear does rub against the back of the trigger ledge and has to be nudged forward.

[unclerandy]

Yeah the MIM parts suck. Still don't have a smoking gun though. Its my understanding that MIM parts would crack or break before bending if something were to fail. I'm expecting to take it to a S&W master smith the first of the week in person. I'll see what he has to say and report back. After reading most of the Kunnhausen manual there are other issues as well. Issues I don't think would cause this but.....Even though its not my gun its pretty disappointing to see what S&W is producing and selling for 800-900 dollars. Kind of junky.