32-20 with heeat treated cylinder?

I have a question for the experts on the older S&Ws:
We have all seen K frame 357 magnums and know that a steady diet of high pressure loads can have some effects on them if the end shake allow the cylinders to batter back and forth. But I read over and over how the higher pressure (rifle) loads for the old 32-20 is bad for S&W revolvers . I also understand that the 32-20 K frame guns had heat treating of the cylinders began with serial number 81287.
So, the pressure of a 357 Magnum run in the 36,000 PSI range but I only find pressures of the "rife load" 32-20 being 23,000 and the 32-20 chamber walls are a lot thicker then the walls on a 357 magnum. So can someone tell me why we are warned against using such loads in the K-frame guns when the 357 mags are obviously made for higher pressures then the 32-20 ever had and are fine despite the thinning of the cylinder wall ion the 357?
I have used Colt SAAs in the past in 32-20 with some very fat loads and the guns were just fine. Now I understand the cylinder of a Colt SAA is larger then that of a K-frame S&W, but the 32-20 K-frames are far thicker then the 357s? Is the steel used in the 357s a different alloy? Is the heat treatment inferior in the 32-20?
Of is this just a case of people regurgitation information that was written long ago who simply were wrong and never put to the test?

What say ye?

By the time 32 Winchester S&W were being manufactured, the standard tensile strength of steel was over 30,000 psi. Standard revolver pressures are stated in several places as around 16,000 psi. Rifle pressures listed in SAAMI are in CUP, but at pressures below 30,000, CUP and psi are very similar. Rifle pressures were listed at the equivalent of around 21,500 to 22,500 psi. The safety factor of vintage 32-20 revolver without cast hardening is likely over 2X which is totally adequate for even rifle rounds, which I bet has been shot in just about every revolver out there at some point in their life, It is NOT something you want to do today! Keep the loads and bullets light and I bet they will go "clean through" paper! Also, there is no modern 32-20 ammo out there today made by the major manufacturers that would not be safe for your revolver.

There is a good post about the same topic below:

Maximum pressure for an old S&W 32-20

When I was a teenager I loaded 32-20 ammo for one of my school friend's dad. He owned a Marlin rifle, a Colt Bisley and a K-frame S&W, all in 32-20. I loaded ammo for him and both he and I shot it in all 3 guns. I got the load data from an article in Guns magazine. I do remember that some of it was considered "hot' for the cartridge as compared to factory loads. yet in all 3 guns it was excellent and more accurate then any factory load we had tried. That was 50 years ago now. Since that time I have rear and read and read over and over how using such loaded in "old guns" is somehow harmful, but knowing that gun steel doesn't break down with age (Like I have) and if cared for such guns are as good today as the day they were made, I can see no reason a 32-20 can't be loaded to 24,000 or even 28,000 PSI which is still lower then any 357 magnum and if the cylinders were made from the same steel and had the same heat treatments, the 32-20 should be substantially STRONGER then the cylinders on M19 or M13s. In such guns because of the age, I thought I'd ask those on the forum if they know about the steel alloys and the heat treatment processes used by S&W from the 40s and the same information from the 60s and 70s. If there is no difference in steel or in heat treatments it's obvious the 32-20 is NOT weak and is not dangerous to load to the higher pressure, but still below the factory standard for 357 mag)

The bullets I used in the early 70s were SWC and dropped from the mold at 99 grains when cast from WW metal. I still have the mold. I did use both Unique and 2400 powders, but also some old WW630 (no longer made) and HS7 if memory serves. The "weakest" of the three guns was probably the S&W K-frame but even that gun used all the loads I made, and the shell fell from the chambers with very little pressure on the ejector rod. All brass seemed fine. Now I admit, I was just a kid in those days and so I took the information from the Guns Magazine as if it were gospel, but obviously the loads were fine and we shot many thousands of them. I found the 32-20 to be a very "user-friendly" shell in a revolver. Loaded hot it still kicked less then a hot 38 special and shot flat REAL FLAT. I shot numerous jack rabbits and a few fox and coyotes as well as some badgers and a bunch of skunks with those 2 revolvers but I made most of the kills with the S&W. The idea that the K frame S&Ws revolvers could be dangerous to use with "hot ammo" has stuck in the back of my mind for 1/2 a century now. I know what I did and I know it was just fine. Yet I keep reading that it's not fine.
So I thought I'd ask others out there in "cyber land" for input, because unless the steel in the 32-20 is different in some way then the steel in a M19, there seems to be NO reason a 32-20 could not handle pressures up to 36,000 PSI easier then any K-frame 357 mag could. Show me why I am wrong please.

I hope you guys are right. I have several older 32-20's.

I bought the hype and acquired a couple of Ruger tanks for hot 32-20 loads; the Buckeye and the Blackhawk 8. I'm thinking my T/C shoots those hot ones as well.

There is also a old belief put forward that better steel didn't happen till the 1920's. However, I've never seen numbers about how much better.

The 32-20 was my FIRST caliber as a young cowboy in Texas in both a first gen Colt SAA and a Winchester lever gun.
So I loved it then and I still love it now.


szihn, nice post to get started here. Welcome !

Prescut

My first .32-20, bought after reading a Skeeter Skelton article, was produced pre World War ONE. I mostly shot factory and factory equivalent reloads. Later, I bought a copy of Cooper on Handguns. Colonel Jeff had a number of pet loads, including one for the .32-20. I don't remember the load, but it was healthy charge of 2400 under a 115 grain bullet. That loading was definitely hotter than factory and LOUD! I don't think I would use it in a vintage revolver again. It would probably be fine in a rifle.

Regarding szihn's comments comparing the K frame .32-20s and K frame .357s: my feeling is that we are compering apples to oranges. I believe, and have no proof to back it up, that a late 1920s .32-20 K frame cylinder is not as strong as a 1955 and later .357 K frame cylinder. IIRC, the heat treating that the pre WW II revolvers received only brought them up to the standard steel strength used in the post WW II non Magnum revolvers.

Miley Gil and others, don’t forget that Phil Sharpe used a 38 Special Outdoorsman to develop what would become the 357 Magnum. And many 38 Special N frames were converted to 357 by merely reaming the chambers deeper.

Kevin

Standard steel yield strengths did not change from 1900 to 1035. There were three steels available prior to 1960. The issue is what steel did S&W use? K33 (Structural), k40 (Intermediate), and K50 (Hard) were the three standard grades available during the first half of the Twentieth century. They offered yield strengths from 30,000 psi to 50,000 psi. Of course there were specialty steels made throughout this time period, but I have never found the grade steel used in the factory back then.

All grades are fine for a load that generates around 16,000 psi, but if you intend to try to get near 30,000 psi, you are on your own. Remember that yield strength numbers are just as they sound. The metal will go beyond elastic deformation and start to yield to a point that it will remain deformed after the yield pressure is applied. Repeated yield pressure application will almost certainly cause failure over time. Safe working pressures are generally half of yield strengths.

Heat treating is not all it is cracked up to be (pun intended). Yield strength will rise, but as heat treatment is applied, the steel gets more brittle. There is a balance that must be maintained so as not to make the steel too brittle to the point where failure might occur. The added strength of heat treated metal is not all that much higher than starting numbers, so the value of heat treatment in pressures below 20,000 psi are negatable.

To complicate matters further, the amount and type of heat treatment one applies to metal will have varying effects. Typically, steel yield strengths can be improved by 10% to 40%, but since we do not know what steel S&W starred with, and how long and what type of heat treatment was applied, it is anyone's guess what the improvement actually was in the factory?? My only guess is that they kept the treatment mild so not to embrittle the steel and maybe added 10% to 15% strength to the metal.

My advise is to go buy a gun that will do what you want instead of conducting some potentially dangerous experiments with a gun that is not designed to do what you want!!

There is a ton of difference between the cylinder walls of a Colt SAA and the little K-frame. Remember Colt used the same cylinder for the .45 as it did for the 32-20. Also remember that Winchester used basically the same design to build the Model 92 that it did the 1866, probably the strongest and most complicated of Winchester lever actions. There is a world of difference between Winchester inherent strength and that of K-framed Smiths, even Colt. Elmer loved shooting his SAA 32-20's, I don't recall him blowing any of them up. I have two different loads for 32-20, rifle and pistol. You can't hurt a Thompson Center Contender barrel and action so throw anything you want to try at it but go gently with a K-framed Smith especially an older model M&P. Those early developers probably damaged quite a few actions along the way. There is nothing that says you can't load a +P 38 Special in an early revolver, as was mentioned it would not be wise to make a habit out of it. In my 1917 carry revolver I have it loaded with Federal +P 200gr. expanding bullets, when I take it to the range for a bit of practice I usually unload the rounds it is carrying, then switch over to 200gr. plated bullets for the rest of the event. I would not ever want to go through an entire box of those +P bullets in one event, a box has lasted me for years and given the few boxes I have I figure I'm good for life. I had a gunsmith friend of mine fit and install a customized hammer and while he had the piece had him check everything out. He is a Smith armorer with all of the proper frame tools and it checked out in perfect shooting order with just the slightest tweak, he said "Keep doing what your doing."
I don't shoot my 32-20 K-frame as much as I used to, it is currently serving purpose as my wife's kitchen gun. It is loaded with Winchester white box factory stuff and shoots it very well. The Winchester 92 doesn't get shot enough lately either.
I used to enjoy reloading and shooting the 32-20 but today spend more time shooting .44 and .45 acp/ar.

If I understand the question, it's whether the K frame could handle higher pressures above 25,000 on a regular basis.
It is clear that several gunsmiths and lots of individuals have reamed their k frame 16-4's 32 H&Rmag to accept 327fedmag which is rated 45,000psi.
I've always had my questions about that practice, but clearly it has been done successfully many times.


Prescut

357 mags go up as high as 35,000psi and 327 mags hit the 45,000 but the 327 is smaller so has more cylinder wall thicknesses. case OD OF 357- .379 vs .337 for 327 so 327 has .021 more cylinder wall. It is not a bottle neck so more wall than a 32-20 also but the 32-20 still has a smaller base than a 38 0r 357 at .354 so it has .0125 more cylinder wall than a 357. so it should take more pressure with similar steel or make up some for having slightly inferior steel.

ALSO. Working pressure is directly proportional to wall thickness and inversely proportional to diameter. In other words, for tubes with the same thickness, smaller diameter tubes can withstand higher pressures than larger diameter tubes. So, a 327 with a .125 wall will take more pressure than a 357 with a .125 wall.

But, think of this S&W has produced 6 shot 327s mags in J frames with a smaller cylinder than a K frame. K frame 1.446 and J frame 1.306. So, a J cylinder is .140 smaller

As to what steel S&W used (and when), this from a March 1934 letter from D.B. Wesson to a customer asking about the heat treatment on his .22 Outdoorsman:

"The steel that is used in the cylinder of the K-.22 is identical in formula with that used in the larger calibers, but it is not heat-treated after machining as the great thickness of the cylinder walls do not demand any further strengthening." No surprise there, but then he says that steel could be used in any gun they make without strengthening. Specif. "As a matter of fact, even in our larger calibers the steel as it comes from the mill shows a tensile strength in the neighborhood of 80,000 lbs., which does not make the additional strength gained by treating a necessity----------." But then he says they treat it anyway. Specif. "-------but we do very much prefer the greatly increased factor of safety that is obtained with the 130,000 lbs. elastic limit that the treating gives."

Now I don't know why he spoke of tensile strength on the one hand and elastic limit on the other, because as near as I can tell they're sort of the same---and sort of not the same; so perhaps Gary, who's forgotten more than I know about this stuff, can straighten it out for us.

Ralph Tremaine

Proportional limit - Limit till which stress is Proportional to strain . Linear relationship. Slope of graph in this region is a constant and is the young’s modulus. Hookes law is obeyed here. Not the same as elastic limit. This occurs first in the stress strain curve.

Elastic limit - Limit within which body reaches original configuration on load removal. Slope of graph is not a constant. This is not the Proportional limit. This occurs after the Proportional limit.

Thus, there is a small region between elastic limit and Proportional limit.

Yield limit - Point which signifies the start of plastic deformation. But this does not signify the end of limit of elastic deformation. End of elastic limit is signified by elastic limit.

Thus, there is a small elasto plastic region between the elastic and yield limit where deformation is neither true elastic nor true plastic.

Resilience - Area under the stress strain curve within the proportionality limit (energy absorbed during the linear limit)

Proof resilience - Maximum energy that can be absorbed during the elastic limit , that is till the Proportional limit.

Proof stress - Stress corresponding to the Proportional limit.

rct269 said:

. . . Now I don't know why he (DB Wesson) spoke of tensile strength on the one hand and elastic limit on the other, because as near as I can tell they're sort of the same---and sort of not the same; so perhaps Gary, who's forgotten more than I know about this stuff, can straighten it out for us.

Click to expand...

They are kind of the same, but different. Elastic limit is just as it sounds, a pressure that when released allows the steel to return to original dimensions. Exceed elastic limits and the steel will stretch and remain. Repeated applications of excessive pressures will continue stretching until metal thins to the point of rupture. Shooting is certainly a repetitious exercise and excessive pressures should ultimately cause failure.

Tensile Strength is the maximum stress that a material can withstand while being stretched or pulled before failing or breaking. That means that tensile strength will always be higher than elastic limit, but this term is not as well defined.

So exceeding elastic limits will cause deformation and over time can cause failure. Tensile strength, on the other hand can cause failure with a single application of that type of pressure.

To complicate further, there is also the term yield strength. Yield strength is very much like elastic limits, and is defined as the stress a material can withstand without permanent deformation or a point at which it will no longer return to its original dimensions (by >0.2%) So elastic limit is the lowest, yield strength is slightly higher, and tensile strength is the ultimate pressure before failure.

The deal with 32-20 is that it is an old black powder round that was loaded for both revolver and rifle by filling the case with powder and slightly compressing it with the bullet. Pressures were the same (around 16,000 psi) for both firearms, but velocities increased as the barrels got longer. With the introduction of smokeless powders, the limits of pressures were erased and it was found that you could push a 115 grain jacketed bullet over 2,000 fps in a rifle. Pressures for these old-time rounds are hard to find, but some quotes of 30,000 cup are documented. That would equate to something near 30,000 psi so it would not be wise to use in any revolver.

Today, there is no 32-20 standard manufacture that exceeds 16,000 psi, and even Remington Express Rifle loads are close to that pressure. When the caliber was introduced in S&W revolvers, the Model 1899 was first. Standard structural steel was about 30,000 psi tensile strength in the very early 1900s, so using a safety factor of 2X, you get working pressure limit of 15,000 psi. By the 1930s, steel strengths were greatly increased to 50,000 psi and some alloys could achieve the numbers DB Wesson quotes.

There is no question that the 32-20 S&W has a lot more steel than the 38 Special, but the question of whether a 1930s and later revolver can take high pressure loads has never been properly tested or answered. No testing has ever done to my knowledge and there could certainly be some weak points in design other than just the thickness of the barrel and cylinder that would prevent one from trying it. I for one am not a risk taker, so standard or better put, "sub-standard" loads are my favorites and the holes in paper looks the same!

All talk has been Colt & S&Ws. The Spanish copies have questionable steel let alone heat treating. I haven’t seen a blown 32/20, but have seen blown 38sp. Myself I don’t see the need to hot rod a 32/20 anyway.

Deep thoughts.........

Drm50 said:

All talk has been Colt & S&Ws. The Spanish copies have questionable steel let alone heat treating. I haven’t seen a blown 32/20, but have seen blown 38sp. Myself I don’t see the need to hot rod a 32/20 anyway.

Click to expand...

One of my college roommates liked my .32-20 S&W so much he went looking for one for myself. The only one he was found was a Spanish copy. We went out and shot it and accuracy was so-so. Worse, when he ejected the fired brass, the cartridges resembled Weatherby cases, with a sharp angle at the top, instead of the gentle taper.

My "research" revealed that heat-treated cylinders for the .32WCF hand ejectors began with serial number 81287 in (probably) September 1919. I have one that numbers about 2400 revolvers previous to that serial number (if my research is correct) and shipped in August of 1917.

I certainly agree with all who believe firearms this old and fine don't need to be tested. I hand-load for the entire inventory and keep velocities for 100 grain lead bullets to 900-950 fps or under. As an aside I have a Colt Official Police in .32-20 and while not quite as beefy as a SAA in .32-20 it has a lot more steel around the cartridges than my treasured S&W Model of 1905 4th change. I also have a .32WCF Colt Police Positive Special from early 1928 and it, too, has more steel than the S&W cylinder but not quite as much as the Official Police.

Completely agree with glowe (paraphrasing here) that heat-treatment makes a difference but maybe not as much as we'd like to think.

How would one go about testing a hundred year old 32-20? Also, just because a gun is still functioning after that period of time, it is not necessarily safe to use with high velocity loads. I regularly shoot 93g RNFP at 750 fps and it is more accurate than faster loads in most of my revolvers, so see absolutely no reason to push it higher.

I started loading for this caliber over 40 years ago, using even older reloading manuals. My first was a shooter variety 6.5" 1908 revolver, which I only loaded using published data. Shot the gun for a few years before I got my chronograph. I was astonished to find that my go to load ran at over 1200 fps with a 115g LRN. That is way too fast and I immediately lightened the bullet and lowered the powder level until I was under 800 fps and never felt I needed anything faster.

BTW, the fastest revolver loads in my Lyman are maximum 899 fps for a 100g bullet, so loads over 900 fps are beyond the max load available for those listed and are totally unnecessary.