Smith And Wesson Forums banner

1 - 18 of 18 Posts

·
Registered
Joined
·
36 Posts
Discussion Starter #1
I have two older K38 five-screw target revolvers. One just has a serial number...no "k" or "M14" marked inside the frame. That one is very easy to open the cylinder. However the other one, marked with a "k" in front of the serial number and "M14" (no dash), inside the frame, has gotten a little hard to open either empty or after firing. I only shoot very mild cast bullet loads...that is all I have ever shot in ether one of them...thousands of very mild loads.

The problem is NOT dirt...I have taken it down and cleaned it very diligently. There is no apparent reason for its balkyness at opening. The bolt is pushing flush with the frame when I push on the thumb piece and locking bolt out on the barrel lug is moving free and easy.

I would really like to get the cylinder on the M14 to open as free and easy as the older K38, but I am at a loss as to why it has a tendency to take so much force to open it compared to the older shooter.

Any ideas? Have you gunsmiths run across this before?
 

·
Registered
Joined
·
5,183 Posts
The cylinder not opening and closing smoothly on a K frame can be many things . In desending order ill give you the run down from most possible to least possible.

1. Loose Extractor rod ( tighten up extractor rod with some spent rounds in the charge holds . ( Reverse Threads

2. Worn Bolt the bolt that pushes on the extractor rod tip in the frame is worn. fix is replace the bolt .

3. Dirt under the extractor star

4. Ammunition rubs on frame and primer flow..

5. Worn locking bolt getting sloppy and rocking in the bolt cut.

6. Loose thumb piece nut on the sidd plate.

7. Bent extractor rod.

8. worn yoke screw getting sloppy or to tight

9. Worn yoke button

10, Short or worn center pin

11, Yoke out of alignment ( gun dropped or cylinder slammed shut. ? )

12, End Shake of cylinder yoke. more than .005 deviation

13, Worn recoil plate / firing pin bushing backing out into cylinder area dragging on the rounds or cylinder

i have to assume that this is a problem with the gun unloaded as well as loaded. That is why I put the ammo problems also. . Good luck hope it works out for you.

Layne12gun
 

·
Registered
Joined
·
36 Posts
Discussion Starter #3
1. Loose Extractor rod ( tighten up extractor rod with some spent rounds in the charge holds . ( Reverse Threads
Extractor rod not loose (K38 this old have right hand threads).
2. Worn Bolt the bolt that pushes on the extractor rod tip in the frame is worn. fix is replace the bolt .
The Bolt pushes out flush with the frame. There is a slight dimple in the end of the bolt where the extractor rod tip touches it, but by "slight", I mean about .0005 of an inch...barely perceptible and logically not enough to cause the problem. The bolt does not seem to be causing the problem.
3. Dirt under the extractor star
The recess for the extractor star and the underside of the extractor star have been scrubbed with a toothbrush...no debris or dirt under it.
4. Ammunition rubs on frame and primer flow..
With ammo, without ammo, makes no difference.
5. Worn locking bolt getting sloppy and rocking in the bolt cut.
Locking bolt has no more apparent clearance than the K38 that opens freely. As a mtter of fact, the bolts on both k38's push slightly (.001-.0005) proud of the frame. It seems that the locking bolt cannot be the problem.
6. Loose thumb piece nut on the sidd plate.
Thumbpiece nut is tight.
7. Bent extractor rod.
I will take it apart and roll the extractor rod on a surface plate...so that has yet to be eliminated as a possible cause.
8. worn yoke screw getting sloppy or to tight
Yoke is tight, no play, not binding.
9. Worn yoke button
What is a "yoke button"?
10, Short or worn center pin
I have considered that...the gun may have always been a little hard to open and I may have only noticed it when I acquired the older k38 and had to to compare to the M14. It may be a perception "fault".

11, Yoke out of alignment ( gun dropped or cylinder slammed shut. ? )
Yoke not misaligned, yoke to frame fit is superb.
12, End Shake of cylinder yoke. more than .005 deviation
.007 with fired cases in the chambers on the problem one, .008 with fired cases on the one the opens easily.
13, Worn recoil plate / firing pin bushing backing out into cylinder area dragging on the rounds or cylinder
Both k38's show no more than very minor wear on the recoil place from the tip of the ejector rod. The firing pin bushing is flush with the frame.
i have to assume that this is a problem with the gun unloaded as well as loaded. That is why I put the ammo problems also. . Good luck hope it works out for you.
As per my original post, loaded-unloaded makes no difference.

At this point I have concluded that it may have a congenitally short extractor rod. Inasmuch as they do not cost a fortune, I will order one, install it, and see if it makes a difference.
 

·
Registered
Joined
·
12,778 Posts
The yoke scew has a tapered end that engages the yoke inside the frame. frame. its called the Yoke Button A short extractor rod could be the culprit. Everything i said above is directly from the Armorers manual .
Been mulling this over for a day or so....

I'm thinking the cylinder runout isn't within spec or the forcing cone to cylinder face dimension is too tight or both.
 

·
Registered
Joined
·
12,778 Posts
The yoke scew has a tapered end that engages the yoke inside the frame. frame. its called the Yoke Button A short extractor rod could be the culprit. Everything i said above is directly from the Armorers manual .
Been mulling this over for a day or so....

I'm thinking the cylinder runout isn't within spec or the forcing cone to cylinder face dimension is too tight or both.

Runout and too tight a face to cone dimension can be caused by wear on the cylinder bushing the resides in front of the hand.
 

·
Registered
Joined
·
5,183 Posts
Its really hard to tell without holding the gun in our hands. Were trying to get to the bottom of the problem. ?? i would not suspect cylinder run out unless the gun had a TON of rounds through it. !!!????
 

·
Registered
Joined
·
10,302 Posts
Its really hard to tell without holding the gun in our hands. Were trying to get to the bottom of the problem. ?? i would not suspect cylinder run out unless the gun had a TON of rounds through it. !!!????
Yes, I would agree, except that it appears that my 686 came with a slightly short center pin to begin with and others have reported the same issue. It's not hard to check for it to see, especially with another similar model to compare it to. If the center pin comes out of the extractor rod enough (or at least flush to the tip of the rod), that would answer the question. I was just offering up a possibility that I recently dealt with and to be clear I'M NOT a gunsmith! :)
 

·
Registered
Joined
·
14 Posts
I recently bought a 17-3 that was difficult to open. I found that if I pushed the cylinder back it would open without too much difficulty. I bought the revolver then installed a .002 endshake shim (from brownells) and the problem was cured. BYW, this 17 turned out to be a great shooter (accurate, no problems with chambering or extraction) unlike some of the other 17s and the one 18 I have owned in the past.
 

·
Registered
Joined
·
12,778 Posts
Its really hard to tell without holding the gun in our hands. Were trying to get to the bottom of the problem. ?? i would not suspect cylinder run out unless the gun had a TON of rounds through it. !!!????
Believe it or not but that was one of the issues I had with that 460 that went back to the mothership. It came back with a new cylinder (and I suspect a shim on the cylinder axle as well) and a new barrel and some other stuff too. I feeler gauged the forcing cone to cylinder face dimension and it varied almost 18 thousands in 360 degrees of rotation. I was about ready to pull the cylinder and face it and reset the bushing but S&W handled it instead. After all, it was new (less than 15 down the tube).

I knew it was out of spec by the amount of blowby I was getting. 5 rounds and the cylinder was black.

If the cylinder face isn't dimensionally square to the rotating axis, the cylinder can be hard to open.
 

·
Registered
Joined
·
36 Posts
Discussion Starter #14
Its really hard to tell without holding the gun in our hands. Were trying to get to the bottom of the problem. ?? i would not suspect cylinder run out unless the gun had a TON of rounds through it. !!!????
The gun has a lot of rounds through it but all minimum loads...130 grain cast bullets, 2.9 grains of Clays.

Please explain what you mean by "...cylinder run out...".
 

·
Registered
Joined
·
36 Posts
Discussion Starter #15
The plot thickens.

Today, while examining the offending Model 14, I noticed the after the center pin is pushed clear of its hole it still has the "tighter than the other one" feel.

At that point I concluded that only two possibilities could be in play. Firstly, the crane may not be rotating smoothly in the frame. I eliminated that possibility by removing the cylinder from the crane, and reinstalled the crane (without the cylinder), back into the frame and tested it for travel with the crane retention side plate screw installed. The crane moved through its arc without any apparent drag. So, the issue is not related to the crane.

That left me with only one possibility...the center pin spring being too robust. I pulled the center pin just to make sure there was not some errant carbon causing binding. There was not.

I will order a center pin spring and replace the one already in the gun. If the new spring does not change the force required to disengage the cylinder, I will clip a couple of coils from it, and stretch it out...that should give me a weaker spring and should result in the cylinder being easier to open. We shall see...a new spring is a very modest investment and I can always put the original back where it was.
 

·
Registered
Joined
·
10,302 Posts
OP, since you have a second K38 that opens to your satisfaction, try swapping the cylinder assemblies on the guns and see if the trouble follows the cylinder of the one you're having issues with. That would narrow it down to the parts within the assembly i.e. extractor rod, center pin, extractor star, springs, and rod collar (even the cylinder itself?). You could further disassemble the cylinders and compare each part until you find what you think to be the problem. Just an idea to try before buying parts.
 

·
Registered
Joined
·
36 Posts
Discussion Starter #18
OP, since you have a second K38 that opens to your satisfaction, try swapping the cylinder assemblies on the guns and see if the trouble follows the cylinder of the one you're having issues with. That would narrow it down to the parts within the assembly i.e. extractor rod, center pin, extractor star, springs, and rod collar (even the cylinder itself?). You could further disassemble the cylinders and compare each part until you find what you think to be the problem. Just an idea to try before buying parts.
]


I removed the cylinder from both guns today and tried to put the older K38 cylinder into the newer (yet no model or "K" in the serial number, but still has five screws) gun. However the cylinder and yoke would not fit in the gun in question despite being nearly identical.

If I wish to pursue it any furter, I will have to use the original cylinder and yoke, but will have to swap out the center pin and spring.
 
1 - 18 of 18 Posts
Top