There was mention made of heat treating in a recent thread (here) titled "Questions for those who know about 2nd Generation .44 Specials". The mention made was to the effect the heat treating afforded the later guns made them good----safe. The clear implication was the earlier (non heat treated) guns were not so good---in terms of what sort of ammunition one should use---lest they risk sudden amputation of sundry body parts. Fine.

I suspect we all know heat treating is good because it makes stuff stronger, and stronger is better than weaker. I also suspect relatively few of us know what (exactly) is involved in heat treating, and why it works. That's fine too---and you're not going to get any answers about that here---because I don't know either. The primary reason I don't know is because, when you get right down to it, I don't care. I don't care because I have faith in those who do know----and care.

One such person (who knew and cared) was D. B. Wesson, Vice President, Smith & Wesson. These words of wisdom come to you courtesy of the Smith & Wesson Historical Foundation----and me (because I paid for them---not much, I grant you). The time is March 1, 1934. The context is an explanation of why the steel in a .22 Outdoorsman cylinder is not heat treated. The words are these: "The steel that is used in the cylinder of the K-22 is identical in formula with that used in the larger calibers, but is not heat treated after machining as the great thickness of the cylinder walls do not demand any further strengthening. (The important part is coming up right now.) 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------------". He goes on, but that's the point I wished to make----and it's made.

Ralph Tremaine

And for those who "gots to know", the treatment afforded for the larger calibers raised the "elastic limit" from 80,000 lbs. to 130,000 lbs.-----as in "Some's good, more's better, and too much is just right!"

I forgot one have studied metallurgy and heat treatments. Being a knife maker it is very important.
Iron and carbon don't form steel molecules. No such thing. More of a crystal like matrix. HT changes the relationship of the carbon to the iron and other metals if present.

I believe that the post-Triple Lock N frames have a slightly larger cylinder diameter. With the locking bolt notches over the thinnest part of the chambers, this may make Second and Third Models (as well as other N frames built later) modestly stronger. I doubt that the difference is significant but it is probably there.

Main point here is, all but a handful of S&W handguns were plenty strong enough for the ammunition in use, or developed for, when the guns were designed and produced. I see no benefit in trying to make a 75-100 year old gun into something it was never intended to be by handloading warmer ammo. I like shooting my old .44 Specials, but I do it with factory ammo that closely duplicates the original pressures and velocities.

This supports what Ralph posted:

• Heat treatment was eliminated by order Oct. 12, 1945 for cylinders on the .22 & .32 ‘I’ frames, K22, 32 & 38, and the 44 & 45 N frames, "S&W 1857 – 1945". The 38 N frame is not specifically listed. This could mean that 38/44s never were heat treated and why it's not a good idea to ream and shoot them with 357. The .357 continued to have heat treatment and all subsequent magnum cartridge models. May be cost cutting, improved metallurgy, or more probably, both.

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Jim
S&WCA #819

Question - the part where D.B. Wesson goes on, is the unsaid part "for a .22"? Like this:

"....which does not make the additional strength gained by treating a necessity for a .22". Or is the heat treating not truly considered a necessity at that time for any other calibers?

"Slightly larger cylinder diameters"--See post #3.

That was a new one on me, but there's lots of stuff that's new on me. Here are the numbers from mine: TLT #3976, shipped 02/23/09, 1.695". 2nd Target #58669, shipped 05/14/40, 1.697". 3rd Target #54911, shipped 01/28/41, 1.692".

Another new thing I learned was not all "six shooters" have the locking bolt notches over the thinnest part of the chambers----as was my knee-jerk reaction. I have one Colt "hand ejector". Its locking bolt notches are offset a bit---not much, but they clearly are not over the thinnest part of the chambers. Having now been forced to think about it, I also have a Colt SAA---waiting to be picked up from my gunsmith. I'm thinking its notches are also offset a bit. I'll see about that tomorrow.

Ralph Tremaine

That following "necessity," is: "------------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."

Bottom Line: While they did not consider it a "necessity" (per se) for the larger calibers, they most certainly considered it prudent, and they get no argument from me.

Ralph Tremaine

...heat treating is a two step process...first step heats the steel red hot and then it is quenched...making the steel very hard but also brittle...the second step...called tempering... brings the steel up to a lower temperature...and then it is quenched again...leaving the steel tough...but not brittle...the toughness is the goal of the process...

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A Country Boy Can Survive

This is discussed in "S&W 1852 - 1945" page 215; 2nd Model cyl diameter and cyl window were increased .020".

My two TL targets both have a cyl diameter of 1.693". For reference, my 1917s are 1.705". That doesn't quite get us to the reported .020" 2nd Model difference above.

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Jim
S&WCA #819

Jim,

Respectfully, actual cylinder measurements trump words in a collector book. How could it be otherwise?

Absolutely! That was my point in providing actual measurements.

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Jim
S&WCA #819

The last word, the VERY last word on dimensions of virtually any exterior part of a S&W revolver goes like this: "You can't tell anything from that!"

Those words were spoken to me by one Roy Jinks---probably 20 years ago. They were spoken in a tone which suggested there must be something wrong with me for even asking such questions. Those questions arose from a (factory refinished) RM----which "didn't look right". That which "didn't look right" also didn't feel right, and was in comparison to an original RM---one in one hand---the other in the other hand. It isn't like I have micrometer eyes or fingers, but the differences were such as to cause me to reach for my measuring stuff. The differences were of a magnitude of 6-8-10-12 thousandths---depending on which part was being measured----the refinished gun being the smaller of the two---every place it had a place. I figured it must have spent a goodly amount of time at the bottom of a lake---or somewhat less time in a bucket of acid-----except the bore/chambers were shiny bright---and all there.

So---you can believe your lying eyes or the word of GOD----pick one!!

Ralph Tremaine

It is perhaps noteworthy the refinished gun was a matte blue---not to the extent of the early post WWII products, but a matte finish nonetheless.

I wouldn't worry about the difference in a Triple Lock .455 and a Second Model in .455, but don't think either was heat treated. Even .455 Colt is a low pressure round, let alone .455 MK II. The US Govt. MADE S&W heat treat all .45 M-1917 cylinders, as Colt was already doing. There must have been a reason. It's a hotter load than .455. The M-1917 has had some cylinders crack or blow from handloads. Some were not as hot as one would think.

Ralph noted that the M-1917 cylinder is wider than the .44 Special (?) cylinder, but it also has wider holes bored in it, for wider ctgs. !

I don't think there's any doubt that .38 Special and larger calibers gained from heat treating. A K-22 is another matter, and they did recess the case head area on cylinders for these rimfire rounds.

If you had a .44 Special and wanted to load it hot, a Triple Lock was not the place to do that. Even Elmer Keith admitted that.

This Ralph is pretty sure he didn't say one word about a M-1917---seeing as how he doesn't know the first thing about them---and very likely never had one in his grubby little paws.

Ralph Tremaine

Texas wrongly attributed Hondo's measurements to Ralph. He's forgiven.

The .013" difference Hondo measured is not a lot. I wonder if cylinders made during the push for faster war time production did not just get sanded less or if some of the round stock they were made out of was not held to peace time tolerances.

Rupture pressure in cylinders formulas (actual rupture):

Barlow: 2TS/D
Boardman: 2TS/(D-.8T)
Lame: S(D^2-d^2)/(D^2+d^2),
where T=Wall Thickness ("); S=Ultimate Tensile Strength (psi);D=OD(");d=ID(")
The Barlow formula is mainly used for thin wall cylinders with wall thickness <5% of ID. The other two are used for thicker walled cylinders.
In the past, I have generally calculated rupture pressure using all three formulas, and used the lowest result. Then add at least a 100% safety factor. There is no safety factor built into these formulas.

The maximum yield strength for typical heat-treated ordnance steel alloys (such as 4140) will usually be around 150,000-180,000 psi, with ultimate tensile strength about 10% higher.

Apologies to Ralph and to Hondo. Comes of watching TV while typing and forgetting who posted what . But my basic point was valid.

K-22Fan mentioned possible wartime production sloppiness. I've see a fair number of M-1917 .45's and all seemed well made. But who knows? There were a LOT of them!

What I do think may have happened in WW II is that some .38-200 revolvers were accidentally or sloppily fitted with .38 Special barrels, with slightly tighter bores.

I read in a UK gun magazine that RAF shooting teams got bullets stuck in the barrels with S&W revolvers, but not with Webley and Enfield examples.

No barrel lengths were mentioned, and they said this involved shooting teams. I think they may have had six-inch barrels. Later guns were mainly with five-inchers and there was probably less chance of getting a .38 Special barrel on them as .38-200 production was expanded and likely kept more separate from .38 Spcl. Victory Model production. There could have been some six-inch (or other length).38 Spcl. barrels not yet marked for caliber that strayed into .38-200 production lines.

The ammo was almost surely metal jacketed British service loads. The jacketed bullets would create more bore friction than lead bullets. So, a bore that may be marginally okay with commercial lead ammo could clog with a FMJ bullet. ??

Just a theory. But it wouldn't surprise me, especially in the rush of 1940 production, trying to get guns out the door and to Britain after Dunkirk. And most .38-200's with six-inch barrels were made in that 1940-41 period.

And S&W was on the hook for their failed Light Rifle fiasco. They were eager to get revolvers to the UK to atone for that liability. Some errors may have happened.

My only reason for providing 1917 Cyl measurements was because it might be indicative of the 44 2nd model and 455 2nd model which I have neither of to compare.

My two post war 44 1950 target cyls are 1.702" and 1.708"; on both sides of the 1917's 1.705". All just manufacturing tolerance ranges.

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Jim
S&WCA #819

I don't have anything to offer into the heat treat/or not issue. But after gunsmithing, refinishing and restoring firearms for the last 40+ years, the 1.692, 93, 95, 97 ect different dia's in the guns' cyl from gun to gun are simply nothing but the result of the polishers and how they handled the part.
Everything was polished by hand held operation but against large perfectly balance abrasive wheels and belts.
If you've ever sanded wood with a belt sander or polished metal w/a belt grinder you know how quickly and easily material disappears.
Even at the large end of the spectrum of .005" difference,,that's only ,0025 difference a side.

On a refinish, it starts to be more noticeable with the removal of pits and dents to get to clean metal.
Then measurements can tell a tale sometimes.

Some Colt SAA collectors have taken to carrying a set of simple width gauges to check the frame at various points for refinishing/polishing. Dimension changes outside the normal +/- of what they consider would be a factory original draw concern which may already be there. Then it may only confirm it in their mind.
I can think of a lot of guns that could use a set of those when you go shopping!

and FWIW (someone asked) the Colt SAA cyl locking slots are just barely offset from the chambers.
They can bulge or blow out if cut too deep which was a problem with some late 3rd Gen Colt right from the factory in 45.
The quality was not the best at times during that period of mfg but it certainly did not effect all the production.
Done to spec and the gun used w/loads it was designed for it creates no problems.

In all of this, trying to make the gun perform like something it was never intended to do usually leads to problems.

Actually it is even more involved. Temps necessary for forging cause grain growth. Before hardening it is necessary to normalize and reset grain size, hardening causes steel structures to convert from pearlite to martensite, tempering cycles changes in the martensite. Guns frames are tempered fairly high and not that hard, but solid tensile strength. Carbon moves around in its relationship to iron and HT is all about controlling the dispersal and relationship of the carbon to the iron in the steel matrix. Carbon also bonds with other metals, vanadium, tungsten etc to form carbide in a carbon rich alloy, but gun use alloys are carbon poor. 4140 has around .4% carbon. Iron can absorb about .75% if a steel has more that the carbon will seal something else to bond with and form carbide which tend the brittle and form in the grain boundaries. Hard but not tough. Two different things

I love steel Steelslaver