pre model 10 2in problem

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srnotjr

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Hello I am new to this forum and need some help in diagnosing a problem with my M&P pre model 10 2in. SN# S 912xxx. Just got it and cleaned it . Lots of old grease and stuff in the frame. Completely cleaned and reassembled correctly. Empty the gun functions perfectly,timed, no end shake and a smooth DA pull.
At range, fired 1st round(38 rem wadcutter) ,then gun would not cycle. The cylinder would not turn unless you open up the cylinder ,which came out freely, and reclose it. Then another round and locks up again. All common causes of cyclinder binding checked, extractor rod loose,dirt under the star, hand,cylinder stop all negative. Happens with all types of ammo. Local gunsmith is stumped.

Any help would be appreciated. Thanks.
 
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Correct. It cycles with dry firing perfectly and only malfunctions after you fire a round. It cycles with a full cylinder normally and seems only under recoil to lock up. Cylinder stop goes up and down as it should.
 
srnotjr said:
Correct. It cycles with dry firing perfectly and only malfunctions after you fire a round. It cycles with a full cylinder normally and seems only under recoil to lock up. Cylinder stop goes up and down as it should.
Click to expand...

Is it possible you're dry firing by pointing down at the ground so gravity is holding the hand against the cylinder ratchet? If so, I would suspect the hand spring is not properly installed.

Russ
 
srnotjr - did you pull the hand out of the trigger during disassembly and cleaning?
When reinstalling you must "reset" the hand torsion spring within the trigger.
There is info in the smithing section FAQ's I believe
 
pointing at sky or ground or level made no difference, no movement of cylinder . The hand springs back and forth cleanly. the hand was not removed from the the trigger and it rotates the cylinder when dry firing.Only under recoil does the cylinder not turn. you can really pull hard on the trigger or hammer and it still will not turn. Only after opening or releasing the cylinder latch (openit completely ie swing out) does the cylinder then rotate as it should.
 
srnotjr said:
pointing at sky or ground or level made no difference, no movement of cylinder . The hand springs back and forth cleanly. the hand was not removed from the the trigger and it rotates the cylinder when dry firing.Only under recoil does the cylinder not turn. you can really pull hard on the trigger or hammer and it still will not turn. Only after opening or releasing the cylinder latch (openit completely ie swing out) does the cylinder then rotate as it should.
Click to expand...

Maybe the center pin (locks the cylinder in place) is dirty or gummed up?
 
Do the hammer and trigger return normally to their rest positions after a round is fired and the trigger released?

It's hard to visualize what might stop a cylinder's rotation other than a stuck hand, stuck cylinder stop or protruding firing pin.
 
SAFireman said:
Maybe the center pin (locks the cylinder in place) is dirty or gummed up?
Click to expand...

Excellent suggestion. There is a tapered block on the cylinder bolt and a pin on the cylinder hand that guides the hand away from the cylinder ratchet when the bolt is not completely closed.

In addition to checking for dirt, check the spring and plunger in the rear of the bolt to insure it's in place . . . I've had the plunger launch when removed.

Russ

edit to add: not sure that feature is present on the early post-WWII Model 10s . . . depends on when the hand with the pin was implemented.
 
Last edited:
"edit to add: not sure that feature is present on the early post-WWII Model 10s . . . depends on when the hand with the pin was implemented."

This one would definitely have the cylinder stop spring and plunger behind the screw ahead of the trigger guard. I'd check to see if the springs on both the cylinder stop and hand are correctly installed.
 
Thanks for all the imput.

SAfirman, i am sure there is no junk there as i used 1/2 can of gun scrubber after the 2nd cleaning

linde..will check that

DWalt..sequence is cylinder stop,plunger,sping, screw.

DCwilson..once fired the hammer and trigger will not move move than 1/4inch back even if you let go of the trigger and hammer and try again.
the firing pin does not protrude.
 
Just a thought: have you tried pulling back on the cylinder latch on the jammed gun? If the bolt moves forward under recoil, it would lock up the gun by blocking the hammer. Is there proper spring tension on the center pin? Press down on its end in the rear of cylinder, there should be resistance and snappy return when pressure is released. If not, this may allow bolt to move under recoil.
 
Is the cylinder stop still engaged when you try to pull the trigger? Try slipping a feeler guage between the cylinder and stop to see if that frees it up.
 
linde said:
Excellent suggestion. There is a tapered block on the cylinder bolt and a pin on the cylinder hand that guides the hand away from the cylinder ratchet when the bolt is not completely closed . . .
Click to expand...

Here are two types of K-frame cylinder bolt and hand combinations. Note the pair on the right has a pin on the hand and the bolt has a tapered block on the bottom.



tputto said:
Just a thought: have you tried pulling back on the cylinder latch on the jammed gun? If the bolt moves forward under recoil, it would lock up the gun by blocking the hammer. Is there proper spring tension on the center pin? Press down on its end in the rear of cylinder, there should be resistance and snappy return when pressure is released. If not, this may allow bolt to move under recoil.
Click to expand...

Excellent suggestion. Here is an example of what tputto describes . . . it happens to be a J-frame that was open on the bench but the principle is the same. Note how the cylinder hand is being pulled away from the cylinder.




If the cylinder bolt is free to move rearward, check to insure the small spring is properly installed on the center pin so the pin is pushing firmly against the bolt.


Russ
 
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About 3-4 years ago, I had a similar problem on a Model 28. Tore it apart, cleaned everything thoroughly, checked everything, and couldn't find anything unusual. But that didn't resolve the problem. Then one day it magically fixed itself with no further mishaps. I never knew what caused it. But shortly thereafter I sold the Model 28, as I didn't trust it anymore.
 
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Thanks to all for the awesome suggestions! I will let you how things turn out when i pick up revolver from gun smith this weekend. He is having another guy look at it .
Really great stuff, Thanks again.
Brian
 
Just read this thread and now I have a headache...... Oh, Oh, Oh, the intricacies of the Smith revolver... I never want to open one...Never, never, never!

I really do appreciate those of you who have and can help those of us who try to understand these fine revolvers. Did I say that NEVER want to open one...
 
Hi folks...just an update on the problem, my gunsmith has not been able to check it out yet but promises to do so some time next week.. Thanks for all suggestions and I will post outcome when finished.
 
In addition to checking for dirt, check the spring and plunger in the rear of the bolt to insure it's in place . . . I've had the plunger launch when removed.

Russ

edit to add: not sure that feature is present on the early post-WWII Model 10s . . . depends on when the hand with the pin was implemented.

Russ, If you mean the spring and plunger in the back of the bolt, yes, they are the same (in principal) even back to the 1899 1st Model M&P.
 
The internals of S&W revolvers are much more complicated than any of their semi-autos. Then while the frame dimensions have stayed more or less the same, many revisions of internal parts have been introduced. That then causes the unintended consequence of the wrong part being swapped into the wrong frame by a not very knowledgeable 'parts changer'. IMHO, you ought to get a very well done expanded parts view sheet on your exact model and dash number and compare each and every part with the sheet. And, as been mentioned, compare the placement and execution while working the action with every spring. You do know that you can take the side plate off and watch everything work while dry firing the handgun? Also, at one time there was a clear plastic side plate available to allow one to observe the handgun's internals while being fired by someone else. Just be careful of the cylinder/barrel blow-by products.
 
srnotjr said:
. . . need some help in diagnosing a problem with my M&P pre model 10 2in. SN# S 912xxx . . . Empty the gun functions perfectly, timed, no end shake and a smooth DA pull. At range, fired 1st round (38 rem wadcutter), then gun would not cycle. The cylinder would not turn unless you open up the cylinder, which came out freely, and reclose it. Then another round and locks up again . . .
Click to expand...

In my first reading of the problem I focused on "the cylinder would not turn". I'm not sure why but assumed the trigger was operating normally . . . so concluded the hand was simply not engaging the cylinder ratchet. Two possible explanations . . . the hand torsion spring was not engaged or the hand was being pushed away from the ratchet because the cylinder bolt was not fully to the rear.

Then I read it "locks up" which tells me the trigger & hammer will not operate normally . . . confirming to me the bolt is not fully to the rear and is blocking the hammer. The suggestion by tputto to hold the cylinder release to the rear and attempting to fire the second round would confirm that.

I believe the root cause is the small spring on the center pin that is designed to push the center pin firmly into the recoil shield . . . which in turn pushes the bolt far enough to the rear to clear the hammer block on the bolt.

I suspect the small diameter spring was either left out or (and don't ask me how I know this) on the wrong end of the center pin.

Russ
 
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H Richard said:
edit to add: not sure that feature is present on the early post-WWII Model 10s . . . depends on when the hand with the pin was implemented.

Russ, If you mean the spring and plunger in the back of the bolt, yes, they are the same (in principal) even back to the 1899 1st Model M&P.
Click to expand...

Actually I was thinking of the pin on the side of the hand. I've since verified the pin was not on early post-war M&Ps . . . not sure when the change was made.

Russ
 
update...My gunsmith still not has had the time to fully checkout my revolver. He has been swamped with an estate purchase and needs to take care of that first. I will give him another week or so and then take it back to try all the great suggestions expressed here. Thanks again for all the help . I will post outcome.
 
I agree with several of the comments. Make sure the thumbpiece is fully to the rear
after each shot. If its not, that will definitely lock the hammer from being cocked, and
therein locking up the entire action.

Mike Priwer
 
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