S&W K frame 15 revolver trouble

[ret621]

Not sure, and don't want to go any deeper

I put the sideplate back on today and am far from an expert on what to look for, or what you suggested. That link you sent is GREAT, it shows the K frame internal parts very clearly, and is worthwhile for any revolver fans to look at just for information if nothing else. I plan to take the gun to a smith on Monday for an appraisal. Here is a try at one more pic...I think the 1st one was a double of the same.................

 

[4v50 Gary]

If on single action you are holding down the trigger, the trigger should not go forward faster than the hammer.

If however you are lightly touching the trigger and it goes back faster than the hammer, it could be that all that built up grease is impeding the hammer's fall. My M29 didn't function until I cleaned it thoroughly. The lockwork is gummed up and needs cleaning.

BTW, where's the hammer block safety?

 

[winfried]

Inserting a coil spring you will find often clean end being 90 degrees and flat .one end not so flat and angled somewhat. Where the spring goes in, as in the rebound slide, the bad end must go in first because this end is not moving and has no friction. inserting it the wrong way will cause slightly more friction. Think about it for a while, but this is not the issue here although the rebound spring might be in worngly.

Lets look at the forces adding up to the trigger pull of S&W.

Hammer spring light or heavy makes no difference to this issue

added to this:

Force of rebound spring makes no diffence here if...

Added to this must be the actual friction caused by the hammer spring on the sear.
This friction increases required trigger pull.

Pulling the the trigger one only overcomes the friction of the sear caused by the hammer spring but holds the trigger by now consisting of the force of the rebound slide minus sear friction. If at this point the trigger goes forward, the sear has a negative slope and the sear friction never added to the trigger pull as it should.

My conclusions are now this: If an amateur (I am also one) worked on the DA part to improve it, he would have shortened lets call it the DA sear that would have just resulted in premature release of hammer during DA shooting.

However, since this is a target revolver, said amateur tried to improve the triger pull in SA mode and destroyed the sear to a negative angle. I think it is almost impossible to improve the SA sear of a S&W. What I know about metall work, I assume that S&W uses diamond grinding to do the sear finish.

I am not sure anymore, but I think I learned the hard way by also destroying a sear on a S&W of sorts. I have a hammer and a trigger lying im my junk box. Must be a reason for that.

Regards

Winfried



added to

 

[Mizar]

If the problem is from altered SA notch and the DA hammer sear is catching on the trigger as a result, the OP can try a simple test - cock the hammer and pull the trigger, but don't release it all the way - just force it to stop halfway it's travel. Does the hammer stops also, or it is falling all the way?
And one more question - where is the hammer block - did you remove it just for taking the picture, or it is missing?

Boris

 

[Old Fuff]

I enlarged your photograph and it appears that the front edge of the hammer's full-cock notch is rounded off. If so, this could be the reason for your problem, but shadows in a photograph can be deceptive on something so small.

Try this: Get a wood pencil or wood dowel. Cock the hammer and place the pencil/dowel between the frame and hammer face just under the bottom of the hammer nose (firing pin).

Then without touching the trigger, use your thumb to give a hard push on the back end/tip of the hammer spur. See if the hammer is released and falls. The pencil/dowel will prevent any damage.

 

[Picher]

your photograph and it appears that the front edge of the hammer's full-cock notch is rounded off

That's what I noticed also. It may have been too shallow, or been honed to make it a "better" pull.

I've successfully re-cut hammer notches and re-hardened them, but if you send it to a S&W authorized repair center or to the factory, they'll replace the hammer and probably the trigger.

John

 

[ironhead7544]

Sounds like the trigger stop to me. The screw for adjusting it is the one just behind the trigger in the pic. It appears to be burred up. The trigger stops were more for target shooting are were removed some years ago. If the trigger wont release the hammer then that is most likely the problem.

I cant remember exactly what the stop looks like but the screw controls the amount of stub sticking out of the frame. This will stop the trigger from moving back. You could try adjusting it by loosening the screw and setting it back into the frame a little bit. If that doesnt work I would take it to a gunsmith or send it to S&W.

 

[4v50 Gary]

The screw behind the trigger is for the trigger stop. S&W revolvers don't have an adjustable trigger.

 

[ret621]

Going to gunsmith on Monday

I will be taking the S&W to a local gunsmith on Monday, to be checked out. I certainly realize that it is hard to give a diagnosis without actually being able to see the "patient"! I see a few noted that a hammer block is missing.......it has been that way since I owned it for over 15yrs. I just took the sideplate off a few days ago for the first time. I will update things when I find out. It has been great to see so many members offering their help on this forum, even some from overseas!

 

[rcmodel]

I see a few noted that a hammer block is missing

HArd to say if it is missing as I just assumed it was with the sideplate, and you didn't post a photo of that.

The hammer block looks like a long flat peice of steel with an L bend on top and an oval shaped hole on the other end that hook on the rebound slide pin.
http://www.thehighroad.org/showpost.php?p=4978621&postcount=28

It falls out when you take the sideplate off, so do you have it, or not??

rc

 

[Learmorer]

After looking at the photos, it appears to me that the sear is a replacement, and is too long. When the sear is fitted at the factory, the new (unfitted) part is blued all over. The end is filed shorter until it clears the trigger (which is called the long cut) and then a bevel is filed on the bottom front edge (which is called the short cut) . New S&W used to have these angles filed in, removing the bluing on the filed end. The part in the pictures appears to not have the angles, and to still be blued on the end. When you buy a new (unfitted) part, it is always too long when you take it out of the bag. Does anyone else remember when the repair parts came in little manila paper envelopes?

It has been 20 years since I worked on revolvers on a regular basis, but I recall that I always found the filing to be tricky work. The difference between too long and too short is just a few thousands inch, literally one stroke of the file. Still, I didn't scrap many parts, you just have to go easy when you get close.

I have had to re-time a couple of new-in-the box guns, but this is VERY rare, and they were made in the 80's when quality hit bottom. That was when we switched to auto pistols.

That is the best I can tell from the pictures, and would cause the trouble you described.

 

[ret621]

rc was correct on hammer block/sideplate

I dropped the gun off today and was told I will hear in a day or two what he found. He did test it as I suggested, but made no commitment on what was wrong. Yes, the hammer block was in the sideplate, which I did not show a pic of. I used a very small dab of grease to hold it in place as I re-fit the side plate, and was glad to see that it went together as well as it did.

 

[Old Fuff]

He did test it as I suggested, but made no commitment on what was wrong.

Which is understandable. There could be several causes and he hadn't had a chance to really examine the gun to determine which. All you (and we) can do is wait.

 

[Jim K]

The trigger stop (overtravel stop) could be, or at least have contributed to, the problem. Here's how. Some folks played with the trigger stop with the idea of getting the release as fine as possible. The problem is that in doing that, they got a condition where the trigger at the fully back position was sitting right on the edge of the hammer notch and release depended on slop in the trigger and trigger stud, giving a very short release but not a clean one. Eventually, the hard trigger chipped the edge of the hammer notch, and started to wear it down.

But mostly, my real world experience indicates that many of the folks who mess around with the trigger stop (and someone certainly did) also tend to fool around with triggers and hammers. And trade the gun when things stop working.

S&W replaced that style trigger stop with a simple pin inside the rebound slide spring. It is a lot cheaper, works (after a fashion) and is less subject to abuse; I don't know if they still use it.

Jim