K frame 38 vs 357 cylinder metallurgy?

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Model29-26.5

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There is a thread going on the 1961-1980 about a model 14 that was converted to 357 magnum.
Some folks commented that if a magnum round fit, that it would be good to shoot.

I was under the impression that the metallurgy was different, and that the metal was annealed differently in k frame magnums?
However, there are people saying that a 38 cylinder can be converted to accept a 357 magnum round?
Am I missing something??

I would understand if a model 19 cylinder was used in a model 14, and the barrel inside the frame window,was shortened a little in order to allow for the extra cylinder length.

Thanks
 
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Years ago, I asked Dr. Jinks about fitting a .44 Magnum cylinder into a M544, which is a .44-40. He advised against it, as he stated the heat treatment of the frame was different between the M29 and the M544.

That said, I personally believe by using a magnum cylinder in a non-magnum frame, limited use of light magnum rounds would probably be safe.
 
In my mind, all K frames are “limited use” with magnums, even if they came that way from the factory……both for the longevity of the gun and the comfort of the shooter.

Also, our limited use may well be a lifetime of use for the typical shooter who’s had the same box of ammo for 10 years.
 
I do not think that S&W has ever officially stated what all the differences in heat treatment is between the 357 Magnum K-frames and all the lower powered cartridges chambered in the K-frame. People have successfully converted 38 Special frames to 357 Magnum by fitting a 357 Magnum cylinder, so if there is a difference, it may be only in the cylinder.
 
The heat treatment of the cylinder I get.
That would be fitting for instance a model 19 cylinder to a model 15, and shortening the barrel and recutting the forcing cone.
If the model 19 cylinder is he treated then I totally get it, but if they are boring the model 15 cylinder to take Magnums, then I don’t know?
When they talk about how the model 19 pay frame Magnum models were “Developed”, if the metal is the same, then all it would require would be boring, a 38 cylinder differently?
I would be interested to hear what doctor Jinx would say about this.
Thanks
 
I've heard of folks boring out .38 cylinders so that .357 rounds would chamber but I've never seen someone fire one of these conversions. I'd be mighty hesitant to shoot one myself.
 
I and others who have attended the S&W Armorer's School have indicated in the past that when we were at S&W we all had asked specifically if there is any difference in K-Frame revolvers in either the materials or heat-treatment between .38 Special and .357 Magnum models, and the answer we received is that there is not any difference. One of the others was there in 2001, and I got this same answer when I was there in 1974!
 
Alk8944 said:
I and others who have attended the S&W Armorer's School have indicated in the past that when we were at S&W we all had asked specifically if there is any difference in K-Frame revolvers in either the materials or heat-treatment between .38 Special and .357 Magnum models, and the answer we received is that there is not any difference. One of the others was there in 2001, and I got this same answer when I was there in 1974!
Click to expand...
Why is it that I can never seem to remember this?
 
Alk8944 said:
I and others who have attended the S&W Armorer's School have indicated in the past that when we were at S&W we all had asked specifically if there is any difference in K-Frame revolvers in either the materials or heat-treatment between .38 Special and .357 Magnum models, and the answer we received is that there is not any difference. One of the others was there in 2001, and I got this same answer when I was there in 1974!
Click to expand...

That is good to know.
Finally!
So my next question would be, why are the Magnum cylinders longer??
If a 38 cylinder can be bored out to shoot a 357 magnum, why would they have made the magnum cylinders a little longer on the model 19??
I know they did the cylinder rod shroud, and that would’ve been the main difference when the K frame magnum came out I guess, but why the longer cylinder?
Thanks for the input, folks.
I had been misinformed about the heat treating.
I heard that Elmer blew up a bunch of guns During experimentation… and all kinds of stories like that. I know his intervention was primarily the 27 but I figure he would’ve had something to do with the 19, too?
 
If you notice, the cylinder is also longer on an L-frame .357 Mag than any N-frame .357 Mag. Why is this?

I suspect this is because the N-frame design dates back to 1935 and the L-frame was a totally new series from 1980 and modern ammunition evolves.

As to the subject of metallurgy and heat treatment, these would be valid concerns when discussing examples from 80-100 years ago.

In the world of modern and volume manufacturing, it would be a logistical pothole to have two different groups of cylinders with different metal make-up or heat treatment. You would have to stock and supply more items and all hell would break loose if someone grabbed the wrong part.

If we are talking about post-1958 S&W revolvers, I think it’s silly to suspect there are -ANY- inferior cylinders that were not made to modern specs and just as silly to assume that some can handle 35kpsi while some are safe with only 17kpsi.

That’s just not modern manufacturing.
 
Model29-26.5 said:
…
So my next question would be, why are the Magnum cylinders longer??
…
Click to expand...

My thoughts are the cylinders were made longer to accept the 158 grain bullets when seated in the 357 magnum case. There are several bullets of that weight that need to be seated deeper to fit in the cylinder.



Model29-26.5 said:
I heard that Elmer blew up a bunch of guns During experimentation… and all kinds of stories like that. I know his intervention was primarily the 27 but I figure he would’ve had something to do with the 19, too?
Click to expand...
A lot of folks “claim” to have been the reason for the Model 19 but the stimulus can easily be attributed to Evaluators Unlimited.

Kevin
 
I can’t speak of widespread the practice was but on the late 1970’s a Officer brought a .357 Magnum chamber cutting die and did a brisk business recutting the chambers of individual Officers .38 Specials of several different departments to .357 Magnum. This was practical if only 110 and 125 gr. JHP was used. There were never any reports of problems with the modification.
 
Model29-26.5 said:
That is good to know.
Finally!
So my next question would be, why are the Magnum cylinders longer??
If a 38 cylinder can be bored out to shoot a 357 magnum, why would they have made the magnum cylinders a little longer on the model 19??

The reason the .357 Magnum K-Frame cylinder is longer is so in the event of "bullet pull" as a result of recoil with the heavier recoiling cartridge there is more room before the bullets would cause lock-up of the cylinder from the bullet possibly extending from the front of the cylinder. The extra length is not needed for any other reason as the standard .38 Special cylinder is adequately long for the .357 Magnum cartridge.
Click to expand...
If you compare the cylinder length of the Air-weight M&P (Model 12 series) with the model 19 cylinder you will find the Model 12 cylinder is the same length as the Model 19 cylinder, for exactly the same reason. The Air-Weight revolvers tend to have more recoil-induced bullet pull because they are so much lighter than the steel framed guns. The Model 12 had the longer cylinder before the Model 19 was ever introduced!
 
OlongJohnson said:
The Special cylinders being shorter gives them less rotational inertia, so for people who want to do a lot of DA dry fire and rapid shooting, it's easier to get the cylinder rotating and it hammers the stop notch less when it locks up.
Click to expand...
I believe rotational inertia would have to do with the diameter of the cylinder, not the length. That is why the majority of the custom PPC revolvers were built on K frame S&W revolvers. I borrowed an N frame PPC revolver built by one of the top builders. The action, while superb, was noticeably different than a K frame.

The same with my stock revolvers.

Having said that, I still prefer the N frame.

Kevin
 
I don't believe that any normal 357 load would blow up a K frame 38 special cylinder made in the last 50 years or so if it was reamed to 357.

It has been done many times and not once in the years I have been on this forum has a 38 special cylinder that blew up after being reamed and firing 357 mags shown up. If they would we would have heard all about it many times over.
Think about it a few off kilter front sights show up and it is the topic of the day with guys worrying about sights that might be 1 degree off. Yet not one blown up 38 cylinder from firing 357s and more than a few of them had that done to them.

My question is why ream a 38 cylinder, when K frame 357 cylinders are easy to come by and trimming the barrel shank and adjusting the forcing cone is easy and it doesn't cost that much more for the tools and cylinder than it does a 357 reamer.

A 38 special K frame sporting a 357 cylinder and barrel
 
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It’s interesting that the original question has been kicked around on the internet since the time of dial up modems and monochrome monitors.

It’s always surprised me that nobody has put some retired cylinders and frames on a Rockwell hardness tester and answered the question once and for all.

I’ve long suspected that there is no difference. The logistics of keeping track of different heat treatment for near identical parts would be a nightmare and a significant liability.
 
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