Expanded Chambers?

[Mikey5oh]

Hi guys, I have a Smith and Wesson 640 Centennial that I purchased brand new back in 1991. I sent the gun to Smith & Wesson for a maintenance check. After they inspected the gun, they told me that I had expanded chambers and needed the cylinder replaced. They said it was most likely due to shooting +P ammo. They said that the older 640s are not rated for it. After waiting a couple of months, They told me that they were unable to replace the cylinder because they could not get their hands on one and that basically the gun is a paper weight. I then went to my local Gunsmith who took a look at the gun and said that he saw nothing wrong with it at all.
Not sure if I should go online and purchase a new cylinder and just have it replaced or just keep it as is. Is there a way to tell myself if they are expanded?
Thanks

 

[ontarget]

You could ask your gunsmith to check your chambers with pin gauges. If it's still in spec, I wouldn't replace it.
What made you send it to the factory to begin with? We're there other problems?

 

[Slamfire]

Hi guys, I have a Smith and Wesson 640 Centennial that I purchased brand new back in 1991. I sent the gun to Smith & Wesson for a maintenance check. After they inspected the gun, they told me that I had expanded chambers and needed the cylinder replaced. They said it was most likely due to shooting +P ammo. They said that the older 640s are not rated for it. After waiting a couple of months, They told me that they were unable to replace the cylinder because they could not get their hands on one and that basically the gun is a paper weight. I then went to my local Gunsmith who took a look at the gun and said that he saw nothing wrong with it at all.
Not sure if I should go online and purchase a new cylinder and just have it replaced or just keep it as is. Is there a way to tell myself if they are expanded?
Thanks

I would expect the expansion to be in the cylinder bolt locking notches, or at least one. The question I have is, what the heck was your local gunsmith measuring?

If the factory has determined that any part of your cylinder has exceeded yield, and thusly, stretched and is permanently deformed, that cylinder is toast. Have you ever heard of fatigue life? Pressure vessels have fatigue lives, they expand, contract with every pressure cycle, and few things don't have finite fatigue life cycles. There is even something called SN curves with provide designers a means for predicting fatigue lifetime based on stress cycles. I have seen one fatigue cycle curve where the material under test had been deliberately stressed beyond yield. And it failed much sooner than the materials which had not stressed beyond yield.

Ever had a fire extinguisher refilled? I have, and found it very interesting. Fire Extinguishers are pressure vessels and I found an example of someone killed by a bursting fire extinguisher. And they just don't fill your fire extinguisher, it is tested before hand.

My fire extinguisher was placed inside this thick as heck steel chamber. The chamber and the fire extinguisher were both filled with water.



The fire extinguisher was then pressurized to some standard, which expanded it. The amount of water displaced by the expanded fire extinguisher was measured. And then, the amount of contraction was measured once the pressure inside the extinguisher went to ambient. If the fire extinguisher expanded too much, they would refuse to fill it, they had standards. If the extinguisher did not contract enough, after the pressure was removed, they would refuse to fill it.

This is a pressure release disc, in case a fire extinguisher blows when under pressure



and they had enough fire extinguishers blow, that the paint was removed from these things on the wall.



Anyway, if S&W says the cylinder is toast, find a new cylinder. Don't be this guy



or this guy





or this guy



or this guy



These cylinders fail unpredictably, and no matter how much you think the pistol is worth, your eyes, face, hand, etc, are worth more. You can buy extra guns, you cannot replace an eyeball.

I wish I had the picture a CMP range officer showed me of a firing pin from a striker fired pistol in a shooter's eyeball. It went through the shooter's safety glasses. I have not been back since then, but the whole Organization was so spooked they were wanting shooters to wear multiple shooting glasses. They did not know how many layers of shooting glasses it took to stop a firing pin that blew out due to over pressure, but obviously one was not enough, so two sounded good. Maybe they got to three or four! They were just having a knee jerk reaction.

This guy was trying to explain why a Ruger 44 Magnum cylinder could blow within 650 over pressure loads.


Fatique Life of 4140 steel

http://castboolits.gunloads.com/showthread.php?150409-Ruger-om-44-convertible&highlight=convertible

Just a few thoughts on this. For Background I am a mechanical engineer with a heavy background in failure and fatigue.

I wonder if I could request a high quality photo of the fracture zone of the cylinder? I am specifically interested in the grain structure of the bolt notches.

I put fort the following.

1) Firearms in general (the type we plebeians can get our mits one) are not designed for infinite fatigue life.

2) The Factors of safety used in firearms design are in line with low end of fatigue requirements (usually less than 10,000 cycles).

3) One of the funny things about fatigue is that each time you push the material past its original design point, you lower its expected life.

4) I am looking at this as an older gun with an unknown number of rounds through it. but based on its age a substantial round count seems likely.

5) When these firearms are designed it is generally preferable for something else to go before the cylinder lets go and takes the top strap. Generally this takes the form of the gun wearing loose or the barrel wearing out. But they are designed to handle X rounds at standard pressures.

6) I see alot of folks calculate the strengths of Rugers, but these calculations are only ever performing an evaluation on a straight static pressure basis. This is wrong when trying to determine if a load is safe.

I attached a couple of marked up figures for your perusal

 

[gobsauce]

I would expect the expansion to be in the cylinder bolt locking notches, or at least one. The question I have is, what the heck was your local gunsmith measuring?

If the factory has determined that any part of your cylinder has exceeded yield, and thusly, stretched and is permanently deformed, that cylinder is toast. Have you ever heard of fatigue life? Pressure vessels have fatigue lives, they expand, contract with every pressure cycle, and few things don't have finite fatigue life cycles. There is even something called SN curves with provide designers a means for predicting fatigue lifetime based on stress cycles. I have seen one fatigue cycle curve where the material under test had been deliberately stressed beyond yield. And it failed much sooner than the materials which had not stressed beyond yield.

Ever had a fire extinguisher refilled? I have, and found it very interesting. Fire Extinguishers are pressure vessels and I found an example of someone killed by a bursting fire extinguisher. And they just don't fill your fire extinguisher, it is tested before hand.

My fire extinguisher was placed inside this thick as heck steel chamber. The chamber and the fire extinguisher were both filled with water.

View attachment 1078531

The fire extinguisher was then pressurized to some standard, which expanded it. The amount of water displaced by the expanded fire extinguisher was measured. And then, the amount of contraction was measured once the pressure inside the extinguisher went to ambient. If the fire extinguisher expanded too much, they would refuse to fill it, they had standards. If the extinguisher did not contract enough, after the pressure was removed, they would refuse to fill it.

This is a pressure release disc, in case a fire extinguisher blows when under pressure

View attachment 1078532

and they had enough fire extinguishers blow, that the paint was removed from these things on the wall.

View attachment 1078533

Anyway, if S&W says the cylinder is toast, find a new cylinder. Don't be this guy

View attachment 1078534

or this guy

View attachment 1078535

View attachment 1078536

or this guy

View attachment 1078537

or this guy

View attachment 1078538

These cylinders fail unpredictably, and no matter how much you think the pistol is worth, your eyes, face, hand, etc, are worth more. You can buy extra guns, you cannot replace an eyeball.

I wish I had the picture a CMP range officer showed me of a firing pin from a striker fired pistol in a shooter's eyeball. It went through the shooter's safety glasses. I have not been back since then, but the whole Organization was so spooked they were wanting shooters to wear multiple shooting glasses. They did not know how many layers of shooting glasses it took to stop a firing pin that blew out due to over pressure, but obviously one was not enough, so two sounded good. Maybe they got to three or four! They were just having a knee jerk reaction.

And you just scared me into selling all my six shooters.

 

[Slamfire]

And you just scared me into selling all my six shooters.

Where do you live, and are you also selling your auto pistols?

 

[gobsauce]

Where do you live, and are you also selling your auto pistols?

And you scared me into keeping them.

 

[ontarget]

I would expect the expansion to be in the cylinder bolt locking notches, or at least one. The question I have is, what the heck was your local gunsmith measuring?

If the factory has determined that any part of your cylinder has exceeded yield, and thusly, stretched and is permanently deformed, that cylinder is toast. Have you ever heard of fatigue life? Pressure vessels have fatigue lives, they expand, contract with every pressure cycle, and few things don't have finite fatigue life cycles. There is even something called SN curves with provide designers a means for predicting fatigue lifetime based on stress cycles. I have seen one fatigue cycle curve where the material under test had been deliberately stressed beyond yield. And it failed much sooner than the materials which had not stressed beyond yield.

Ever had a fire extinguisher refilled? I have, and found it very interesting. Fire Extinguishers are pressure vessels and I found an example of someone killed by a bursting fire extinguisher. And they just don't fill your fire extinguisher, it is tested before hand.

My fire extinguisher was placed inside this thick as heck steel chamber. The chamber and the fire extinguisher were both filled with water.

View attachment 1078531

The fire extinguisher was then pressurized to some standard, which expanded it. The amount of water displaced by the expanded fire extinguisher was measured. And then, the amount of contraction was measured once the pressure inside the extinguisher went to ambient. If the fire extinguisher expanded too much, they would refuse to fill it, they had standards. If the extinguisher did not contract enough, after the pressure was removed, they would refuse to fill it.

This is a pressure release disc, in case a fire extinguisher blows when under pressure

View attachment 1078532

and they had enough fire extinguishers blow, that the paint was removed from these things on the wall.

View attachment 1078533

Anyway, if S&W says the cylinder is toast, find a new cylinder. Don't be this guy

View attachment 1078534

or this guy

View attachment 1078535

View attachment 1078536

or this guy

View attachment 1078537

or this guy

View attachment 1078538

These cylinders fail unpredictably, and no matter how much you think the pistol is worth, your eyes, face, hand, etc, are worth more. You can buy extra guns, you cannot replace an eyeball.

I wish I had the picture a CMP range officer showed me of a firing pin from a striker fired pistol in a shooter's eyeball. It went through the shooter's safety glasses. I have not been back since then, but the whole Organization was so spooked they were wanting shooters to wear multiple shooting glasses. They did not know how many layers of shooting glasses it took to stop a firing pin that blew out due to over pressure, but obviously one was not enough, so two sounded good. Maybe they got to three or four! They were just having a knee jerk reaction.

This guy was trying to explain why a Ruger 44 Magnum cylinder could blow within 650 over pressure loads.


Fatique Life of 4140 steel

http://castboolits.gunloads.com/showthread.php?150409-Ruger-om-44-convertible&highlight=convertible

Just a few thoughts on this. For Background I am a mechanical engineer with a heavy background in failure and fatigue.

I wonder if I could request a high quality photo of the fracture zone of the cylinder? I am specifically interested in the grain structure of the bolt notches.

I put fort the following.

1) Firearms in general (the type we plebeians can get our mits one) are not designed for infinite fatigue life.

2) The Factors of safety used in firearms design are in line with low end of fatigue requirements (usually less than 10,000 cycles).

3) One of the funny things about fatigue is that each time you push the material past its original design point, you lower its expected life.

4) I am looking at this as an older gun with an unknown number of rounds through it. but based on its age a substantial round count seems likely.

5) When these firearms are designed it is generally preferable for something else to go before the cylinder lets go and takes the top strap. Generally this takes the form of the gun wearing loose or the barrel wearing out. But they are designed to handle X rounds at standard pressures.

6) I see alot of folks calculate the strengths of Rugers, but these calculations are only ever performing an evaluation on a straight static pressure basis. This is wrong when trying to determine if a load is safe.

I attached a couple of marked up figures for your perusal


View attachment 1078539

Very good info. I had not considered stress and fatigue. I was only thinking about in/out of spec dimensions.
On second thought, I would probably go with what the factory said.

 

[AzShooter1]

Just like my old model 10, it's not designed for +P loads and I've never fired one in it. I've seen a lot of guys shooting +P in .38s and they don't think they are ruining their guns. You are proof that they do.

If Smith says it's unrepairable believe then and save yourself from a bad experience.

 

[Mikey5oh]

You could ask your gunsmith to check your chambers with pin gauges. If it's still in spec, I wouldn't replace it.
What made you send it to the factory to begin with? We're there other problems?

The gunsmith told me he checked them with a gauge. I haven’t had any problems with the gun, I sent it in only because it’s a sentimental piece for me. It was one of the first guns I purchased when I became a law enforcement officer back in 1990. I wanted to make sure it was in pristine condition mechanically after all the years of use it has under its belt.

 

[Mikey5oh]

I would expect the expansion to be in the cylinder bolt locking notches, or at least one. The question I have is, what the heck was your local gunsmith measuring?

If the factory has determined that any part of your cylinder has exceeded yield, and thusly, stretched and is permanently deformed, that cylinder is toast. Have you ever heard of fatigue life? Pressure vessels have fatigue lives, they expand, contract with every pressure cycle, and few things don't have finite fatigue life cycles. There is even something called SN curves with provide designers a means for predicting fatigue lifetime based on stress cycles. I have seen one fatigue cycle curve where the material under test had been deliberately stressed beyond yield. And it failed much sooner than the materials which had not stressed beyond yield.

Ever had a fire extinguisher refilled? I have, and found it very interesting. Fire Extinguishers are pressure vessels and I found an example of someone killed by a bursting fire extinguisher. And they just don't fill your fire extinguisher, it is tested before hand.

My fire extinguisher was placed inside this thick as heck steel chamber. The chamber and the fire extinguisher were both filled with water.

View attachment 1078531

The fire extinguisher was then pressurized to some standard, which expanded it. The amount of water displaced by the expanded fire extinguisher was measured. And then, the amount of contraction was measured once the pressure inside the extinguisher went to ambient. If the fire extinguisher expanded too much, they would refuse to fill it, they had standards. If the extinguisher did not contract enough, after the pressure was removed, they would refuse to fill it.

This is a pressure release disc, in case a fire extinguisher blows when under pressure

View attachment 1078532

and they had enough fire extinguishers blow, that the paint was removed from these things on the wall.

View attachment 1078533

Anyway, if S&W says the cylinder is toast, find a new cylinder. Don't be this guy

View attachment 1078534

or this guy

View attachment 1078535

View attachment 1078536

or this guy

View attachment 1078537

or this guy

View attachment 1078538

These cylinders fail unpredictably, and no matter how much you think the pistol is worth, your eyes, face, hand, etc, are worth more. You can buy extra guns, you cannot replace an eyeball.

I wish I had the picture a CMP range officer showed me of a firing pin from a striker fired pistol in a shooter's eyeball. It went through the shooter's safety glasses. I have not been back since then, but the whole Organization was so spooked they were wanting shooters to wear multiple shooting glasses. They did not know how many layers of shooting glasses it took to stop a firing pin that blew out due to over pressure, but obviously one was not enough, so two sounded good. Maybe they got to three or four! They were just having a knee jerk reaction.

This guy was trying to explain why a Ruger 44 Magnum cylinder could blow within 650 over pressure loads.


Fatique Life of 4140 steel

http://castboolits.gunloads.com/showthread.php?150409-Ruger-om-44-convertible&highlight=convertible

Just a few thoughts on this. For Background I am a mechanical engineer with a heavy background in failure and fatigue.

I wonder if I could request a high quality photo of the fracture zone of the cylinder? I am specifically interested in the grain structure of the bolt notches.

I put fort the following.

1) Firearms in general (the type we plebeians can get our mits one) are not designed for infinite fatigue life.

2) The Factors of safety used in firearms design are in line with low end of fatigue requirements (usually less than 10,000 cycles).

3) One of the funny things about fatigue is that each time you push the material past its original design point, you lower its expected life.

4) I am looking at this as an older gun with an unknown number of rounds through it. but based on its age a substantial round count seems likely.

5) When these firearms are designed it is generally preferable for something else to go before the cylinder lets go and takes the top strap. Generally this takes the form of the gun wearing loose or the barrel wearing out. But they are designed to handle X rounds at standard pressures.

6) I see alot of folks calculate the strengths of Rugers, but these calculations are only ever performing an evaluation on a straight static pressure basis. This is wrong when trying to determine if a load is safe.

I attached a couple of marked up figures for your perusal


View attachment 1078539

Thank you for your reply. I guess i’m better off just purchasing a new cylinder and replacing it.
Better safe than sorry.
Does this seem like the correct one -
https://www.midwestgunworks.com/page/mgwi/prod/294530000

 

[Mikey5oh]

Just like my old model 10, it's not designed for +P loads and I've never fired one in it. I've seen a lot of guys shooting +P in .38s and they don't think they are ruining their guns. You are proof that they do.

If Smith says it's unrepairable believe then and save yourself from a bad experience.

I agree. I’m better off safe than sorry.
I purchased the gun as a back up when I was in law enforcement. The funny thing is, my agency gave us +P ammo and said it was ok to use with it. Go figure.

 

[AzShooter1]

Thank you for your reply. I guess i’m better off just purchasing a new cylinder and replacing it.
Better safe than sorry.
Does this seem like the correct one -
https://www.midwestgunworks.com/page/mgwi/prod/294530000

That's the right one and a good price.

 

[edwardware]

I then went to my local Gunsmith who took a look at the gun and said that he saw nothing wrong with it at all.

If you be aren't experiencing difficult ejection (indicative of a swollen chamber), I tend to agree with your gunsmith. Stop the +P, and look again if you start to get hard ejection.

 

[Mikey5oh]

If you be aren't experiencing difficult ejection (indicative of a swollen chamber), I tend to agree with your gunsmith. Stop the +P, and look again if you start to get hard ejection.

Thank you Ed

 

[JohnKSa]

The funny thing is, my agency gave us +P ammo and said it was ok to use with it. Go figure.

Could be a matter of degree. For example, most guns are safe to dryfire, but if you dryfire a hundred times a day, eventually after years, something will break. That said, I'm having a hard time with the idea that factory +P ammo (even a lot of it) was enough to exceed the elastic limits of the cylinder steel. How much +P did you shoot through the gun? Was this all factory ammo?

 

[Tinman357]

This is why I never, ever shoot someone else's reloads. No matter how much I trust them. No one ever shoots my reloads. Ever. Also, they don't use their reloads in my guns.

I allow others to shoot my guns, I provide the factory ammo. I guess I'm just weird that way. I reload a lot, but I want to know exactly is going through my guns. I've been witness to a few high speed disassembly, and don't want any of mine to exhibit that particular trait.

 

[trackskippy]

The gunsmith told me he checked them with a gauge. I haven’t had any problems with the gun, I sent it in only because it’s a sentimental piece for me. It was one of the first guns I purchased when I became a law enforcement officer back in 1990. I wanted to make sure it was in pristine condition mechanically after all the years of use it has under its belt.

If its not giving you troubles, why not just retire it to occasional use and buy another one if its what you like. Sounds like you got your use out of it and its served you well.

 

[Anchorite]

I’ve got one of those 640s that is 38 only, and not marked for +P. The cylinder walls are thin to the eye, and I’m pretty sure (without looking) the bolt notches are over the cartridge holes.

This thread is exactly why I didn’t have my cylinder altered to use moon clips and go 9mm.

 

[Slamfire]

I agree. I’m better off safe than sorry.
I purchased the gun as a back up when I was in law enforcement. The funny thing is, my agency gave us +P ammo and said it was ok to use with it. Go figure.

You are better safe than sorry. You are not going to find a more Gold Standard than a factory analysis . I assume they sent you a reply in writing so that, if you start shooting the thing, and it blows up in your hand, they have proof you were warned.

As to why your Department said it was OK, Organizations are run by fallible humans. Was it not revealed that the very highest Economic and Medical experts were be a bunch of Clown butts when it came to the 2008 recession and the response to COVID? Decisions come from the mind of a deciding authority, and the incentives of the organization highly influence that decision, and it is folly to assume that either are rational or competent.

 

[Walkalong]

Tough spot, but I would be leery of shooting it. Guns are cheap compared to eyeballs etc.

Can your gunsmith check and fit that cylinder?

 

[Mikey5oh]

You are better safe than sorry. You are not going to find a more Gold Standard than a factory analysis . I assume they sent you a reply in writing so that, if you start shooting the thing, and it blows up in your hand, they have proof you were warned.

As to why your Department said it was OK, Organizations are run by fallible humans. Was it not revealed that the very highest Economic and Medical experts were be a bunch of Clown butts when it came to the 2008 recession and the response to COVID? Decisions come from the mind of a deciding authority, and the incentives of the organization highly influence that decision, and it is folly to assume that either are rational or competent.

You would think that an agency as big as the NYPD would know better than that. G*d forbid something happened, there could’ve been major lawsuits.

 

[Mikey5oh]

Tough spot, but I would be leery of shooting it. Guns are cheap compared to eyeballs etc.

Can your gunsmith check and fit that cylinder?

I agree. Going to order a new cylinder. Just surprised Smith & Wesson told me that they can’t get the hands on one.

 

[Mikey5oh]

Could be a matter of degree. For example, most guns are safe to dryfire, but if you dryfire a hundred times a day, eventually after years, something will break. That said, I'm having a hard time with the idea that factory +P ammo (even a lot of it) was enough to exceed the elastic limits of the cylinder steel. How much +P did you shoot through the gun? Was this all factory ammo?

Safe to say at least 1000 rounds through it.
It was my back up/off duty weapon.

 

[Mikey5oh]

That's the right one and a good price.

Does this cylinder also shoot 357?

 

[Slamfire]

You would think that an agency as big as the NYPD would know better than that. G*d forbid something happened, there could’ve been major lawsuits.

Maybe they have a binding arbitration clause, where the LEO with a missing hand gets a free coupon to Arby's in compensation. You just don't know what their incentives are or why they made the decision.

You do know that big agencies will kick problems down the road, till those exposed to toxic chemicals die, before toxic chemical exposures are acknowledged as a problem. DoD is doing that now, and did it for all the Veterans at the nuclear bomb tests, and for those exposed to Agent Orange.

The US military’s toxic exposure problem is far bigger than just ‘burn pits’

https://taskandpurpose.com/opinion/us-military-toxic-exposure-burn-pits/