In 1955, S&W introduced the Combat Magnum revolver, later to be called the Model 19. To do this, they made a few changes to the K-frame to accommodate the more powerful .357 Magnum round, which before that was only chambered in the large N-frames.

Some time ago, I did a chart on the changes to the .38 K-frames, and it's shown here. In fact calling the Model 19 a K-frame is technically inaccurate - probably should be called a modified K-frame! At any rate, here's a photo illustrating the changes.

John

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- Cogito, ergo armatus sum -

I don't know if the original Model 19s had the overtravel stop but Model 19s had the stop. I had a 4" (can't recall the - number) I carried that I removed the stop. I've since traded the 4". I still have my 2.5" 19-3 with the stop in place.

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183rd FBINA

My M19-3 (1974) has the slot for the stop, but no stop in it. Don't know if the original owner removed it or if it never had one.

Nice diagram, can you change "crane" to "yoke", since that is the S&W term?

Nice chart. Tracks well with my understanding of the changes an in an understandable format too. I've owned four Model 19s over the years and used two of them as an LEO. As I recall, my early ones did have the overtravel stop.

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Keep your powder dry.

Removing the stop was a common modification done by LEOs. The stop could loosen, slide, and would not allow the trigger to travel enough to release the hammer. That's why it was removed from the 4" I had. I carried the 2.5" off duty alot but never removed the stop in it. Always thought the next time I removed the side plate for detailed cleaning that I'd remove it. Then I'd forget to do it.

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183rd FBINA

There's a lot of yokes about
how high a crane can fly.

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Ubi Est Mea

John, thank you for the diagram of the most beautiful revolver Smith & Wesson ever made.

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μολὼν λαβέ

Nice diagram, John.

I, like others, don't agree with the trigger stop statement. Combat Magnums through early 19-4's (1979) came with the trigger stop.
Although eliminated for .265" service and later .312" combat triggers, they were still standard with the .400" target trigger into the -90s.

My 19-3 made circa 1973 still has the trigger stop (just visible below). To the best of my knowledge it was in private hands for decades (no holster wear).

I also have a model 15 with a slot for it and no stop, and that gun was owned by a LEO (still has his badge number on the trigger guard, lol).

My 19-3 has a stop but my 19-6 has the slot but no stop

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-Matt

The 19-4 illustrated is from 1980. At the time I did the diagram I was not aware that the earlier models had the stop. I changed the image in the OP to eliminate any reference to the stop, and changed "crane" to "yoke".

John

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- Cogito, ergo armatus sum -

Are we positive the magnum frame was heat treated over the standard k frame? I know there is talk, supposedly from S&W the frames were the same.

The only thing I heard was that the frame was "strengthened." Whether this was accomplished by updated heat treating, bulk, or both, I really don't know. Maybe Jim Supica can shed some light on this.

John

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- Cogito, ergo armatus sum -

S&W sent out a bulletin advising that the K frame trigger stop be removed from revolvers used in law enforcement.

I believe this was in the late '70s.

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John 3:16
WAR EAGLE!

Yes, they did. Those of us who were carrying 19s at the time removed them. I think I still have a couple floating around in my parts bins.

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Dave Frost

I removed several from M19s and M15s myself for my fellow officers.

The same screw that secures the trigger stop also fits the rear sight on adjustable sighted revolvers where the leaf is attached to the top strap.

I used to have a pill bottle full of stops and screws.

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John 3:16
WAR EAGLE!

I remember seeing a letter like that on the bulletin board at the range when doing qualifications about that time.

I have always read that the frames also received a different heat treatment.

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John 3:16
WAR EAGLE!

Changing the heat treatment would certainly be the most cost effective method of strengthening the frame. Other methods would be to use a different alloy an/or increase the mass of the top strap. I doubt that S&W would use a special alloy for just one caliber of revolver and I do not know that there are any significant differences in the mass of the top strap between K-frames chambered in 357 Magnum vs. lesser calibers.

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VCDL, GOA, NRA

The book does say that "The Model 19 is built on a frame that is slightly larger than a standard K frame in the yoke area."

I believe what I read, but - If so, it is not noticeable on my 19-3 v. Model 15, and in both cases, the top strap measures 7 mm thick, and 17 mm wide, so a least in the crossection they are identical.

I might add, the improved K frame for the Combat Magnum (Pre-19) featured the interlocking side plate design thus eliminating the top side plate screw. This was the first model S&W made featuring this design change.

I think you will find that all modern K frames from sometime not long after the model 19 was introduced, have the same sized yoke and frame

I have a 19-3 and a 10-7 in front of me right now and the top strap on the 19-3 is .647 wide and .208 thick , the 10-7 is .650 and .206 thick. 19- 3 at yoke pivot including frame is .707 and right at ejector rod .640 10-7 is 7.06 and right at ejector rod .647 The 19-3 frame is .820 at the barrel and the 10-7 is .817

I just drug out a M&P 38 from 1951
Top strap width is .651 (wider by about .004 to .001) and .202 thick (.004 thinner)
Yoke/frame at pivot .706 (same as above models +-.001)at the ejector rod .648 (+.001)
Frame at barrel is .812. So it is, .008 skinnier there than the 19-3. The only real change if you considered .008 to be that much

I believe most of the small .001-.003 type differences could well be from final finishing. I have replace a yoke and found the new yoke to be maybe .001-.002 proud. They did change the front profile over the years and the top of the frame at the barrel varies with barrel type.

Another thing to consider on a model 19 over a 10 is that the top strap has had more metal machined off for the sight tang and the sight body. No way the top strap and rear of a model 19 is stronger than a model 10. LOOK at them. Measure. I know just how much material because I have machined it off to mount adjustable sights numerous times.

I know the yoke tubes are the same as I have fit a 2 model 19-3 cylinder to 2 10-7s and one to a 10-2

But over all the difference in frame dimensions from a pre model K frame 38 special to a model 19-3 357 magnum don't amount to anything at all.

I do believe the heat treatment was improved in the 50s, but I can see absolutely no reason that would not have occurred across all frames. Time and cost of a improved treatment over a poorer one being totally insignificant. (I do heat treating and had a friend who ran an industrial heat treat shop) Plus, inventory and liability reasons. I have also used my hardness tester on a bunch of frames, both blue steel and stainless and there is almost no difference there. They are all relatively soft. In fact you need to measure in the A range not the C range. Too soft for C. Their hardness is about the same a mild steel, but hardness is only a small part of the story. With a gun tensile strength is the big factor.

In other words my belief it the difference between a 10-7 frame and a 19-3 both structurally and strength wise is 0 ,Zip, Nada and I have 3 model 10s I have shot repeatedly with model 13/19 cylinders and I plan to keep on shooting them too.

So, uh, "ejector" shroud or "extractor"? "Chambers" or "charge holes"?

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Pickpocket