K Frame & Warm 357

[bamaranger]

S&W addressed the issue of wear and tear on K-frames by introducing the L-frame. I would wager that the K-frame magnums were always intended to be shot mainly with .38's, and loaded for duty with magnums. That practice was common in LE circles in that era. If an agency wanted to shoot a steady diet of mag ammo, the big N-frames were the choice. As training evolved, and agencies began to train with what they carried, the K's began to be fed more and more all up ammo.

Not just any mag ammo either, but the hot flash and blast 125 gr JHP, which was the gold standard for stopping power. As I understand it,the combination of the characteristics of the 125 gr load, and the flats on the K -frames, led to examples of top strap cutting. Plus too, the 125 gr load in the K's was a bit of a handful for a lot of officers, many, maybe most, are strangely, not "gun guys". ( I always thought it odd that one in a livelihood where your life or another's might depend on your ability, the handgun was viewed much as a hammer). Policing was becoming more and more diverse as well, not all cops were burly combat vets with some familiarity with firearms. At the same time, the duty belt of officers was growing more and more of a burden, and the big N-frames, suitable for mag loads, added to the load and resulting clumsiness. Enter the L-frame.

Out of production now for some time, if a cone or top strap goes wonky, there is no easy repair. Many years back I yearned for a 2-1/2" M66 round butt, and still do. If I had one, I certainly would not push it.

[44 AMP]

As I understand it,the combination of the characteristics of the 125 gr load, and the flats on the K -frames, led to examples of top strap cutting.

No, it didn't. The "flat" is a relief cut on the bottom of the barrel, at the rear and does reduce the thickness of the barrel at that point, but it has nothing to do with topstrap flame cutting.

Additionally topstrap flame cutting is not a structural issue, it is a cosmetic issue. The blast of certain hot powders out of the cylinder gap will cut a groove in the topstrap steel, but it is a self limiting thing, and does not cut enough metal to weaken the topstrap.

Forcing cone cracking, on the other hand is a different matter and does deadline the gun. And the thin portion of the barrel where the flat is, is the most common place it cracks.

Even when the K frames (models 19 and stainless versions) went to a steady diet of magnum ammo in police use, (including practice) they served normally for quite a while (like through the 1960s) without abnormally high failure rates, shooting the standard magnum 158gr loads.

When the police switched over to the hot 125gr loads for general use (street and practice) that's when problems with forcing cones began to show up at an abnormally high rate. And while gun legend makes it seem like ALL the guns had issues, very few actually did. While I don't have the actual figures, I understand that the "abnormally high failure rate" was something like 7 guns out of 1,000 instead of 2.

AND, sometimes the failures were due to user error. One case I personally saw was a model 19, where the shooter had badly leaded the bore, didn't clean it, and went to shooting the hot magnum ammo, and the forcing cone cracked, literally because it was abused.

From what I've heard, most of the actual problems were mostly with the early stainless guns (mod 65 & 66) and were the result of insufficient testing before the production and Bangor Punta's push to get guns out the door. Can't say for certain, but that's what I've heard. Make no mistake, some guns did fail, it was a problem and it got fixed, but the tales grew in the telling, and the problem was not as widespread as todays stories make it seem.

At the same time, the duty belt of officers was growing more and more of a burden, and the big N-frames, suitable for mag loads, added to the load and resulting clumsiness. Enter the L-frame.

The weight of equipment officers had to carry did go up, quite a bit, but the L frame guns didn't solve that. Not a bit. With the same barrel length, the L frame weighs exactly the same as the N frame. They are NOT lighter. They just balance differently and have a slightly smaller (K frame size) grip frame.

The L frame was not a solution to the weight of an N frame, they weigh the same.

[dogdoc]

Agree with above post. Problem way way overstated on internet

[Webleymkv]

Originally posted by 44 AMP
Even when the K frames (models 19 and stainless versions) went to a steady diet of magnum ammo in police use, (including practice) they served normally for quite a while (like through the 1960s) without abnormally high failure rates, shooting the standard magnum 158gr loads.

This is exactly right. The Combat Magnum (later designated the Model 19) was introduced in 1955 yet the problems with cracked forcing cones didn't become well-known until the 1970's and 1980's. While some will say that the early guns were shot primarily with .38 Special ammo, I think it has a lot to do with the fact that, at the time the Combat Magnum was introduced, the only widely available factory .357 Magnum ammo used heavier bullets.

Actually, it's quite likely that, early on, a lot of the ammo shot through K-Frames was hotter than what we have today albeit not with lightweight bullets. Much of the data in older loading manuals shows heavier powder charges than that shown today and a lot of the older manuals suggest magnum primers for powders that are loaded with standard primers today. Also, the original factory ammo for .357 Magnum was purportedly significantly more powerful that that made today. Given that the Combat Magnum was introduced only 20 years after the Original Registered Magnum, it's entirely likely that there was still a good bit of the original 1935-spec ammo floating around.

When the police switched over to the hot 125gr loads for general use (street and practice) that's when problems with forcing cones began to show up at an abnormally high rate. And while gun legend makes it seem like ALL the guns had issues, very few actually did. While I don't have the actual figures, I understand that the "abnormally high failure rate" was something like 7 guns out of 1,000 instead of 2.

It's my understanding that the primary issue with the hot 125 gr loads is one of both powder and bullet length. This ammo was loaded with slow-burning powder in an attempt to eke out all the velocity they could get (I once pulled the bullet from a Remington 125 gr JSP and the powder inside looked an awful lot like H110/Win 296). In addition to this, the 125 gr and lighter bullets are, obviously, shorter than their heavier 158 gr counterparts. The problem with this is that the nose of the shorter, lighter bullets hasn't fully engaged the cylinder throat before the base of the bullet has left the case thereby allowing burning powder and extremely hot gas to flow around the bullet and prematurely enter the forcing cone. Also, due to recoil and their shorter length, the 125 gr and lighter bullets will impact the 6 o'clock position of the forcing cone with greater force than the heavier 158 gr bullets will. This is all explained in greater detail in this article by Butch Kent on Gunblast.com

https://www.gunblast.com/Butch_MagnumLoads.htm

AND, sometimes the failures were due to user error. One case I personally saw was a model 19, where the shooter had badly leaded the bore, didn't clean it, and went to shooting the hot magnum ammo, and the forcing cone cracked, literally because it was abused.

I've heard this too. I find it somewhat ironic in that, if the bore were leaded by shooting something like standard 158 gr LRN .38 Special ammo, then the old saw of "practice with .38's and carry .357's" might have actually contributed to the forcing cone's demise rather than prevented it. If the shooter you mentioned had shot his revolver exclusively with jacketed .357 Magnum ammo, his barrel would probably still be in good shape.

From what I've heard, most of the actual problems were mostly with the early stainless guns (mod 65 & 66) and were the result of insufficient testing before the production and Bangor Punta's push to get guns out the door. Can't say for certain, but that's what I've heard. Make no mistake, some guns did fail, it was a problem and it got fixed, but the tales grew in the telling, and the problem was not as widespread as todays stories make it seem.

I've heard this before. I've also heard that the problem was endemic to some of the specimens produced right after they eliminated the pinned barrels and transitioned to crush-fit barrels as, supposedly, they had some problems with over-torqueing the barrels which could lead to cracking early-on. Either way, we're talking about revolvers produced 40+ years ago now and, most that were going to crack due to factory defects probably did it decades ago.

My take on it is this: if you take care of your gun and avoid .357 Magnum ammo with bullets lighter than 140 gr, a K-Frame will likely last several lifetimes of what the average person is likely to shoot through it. I've personally owned two K-Frame .357's, a 66-2 and a 13-4, and both have been shot while I've owned them almost exclusively with .357 Magnum ammunition (I have other revolvers that I shoot .38's in). Both are just as tight and have forcing cones in just as good condition as the day I bought them, but the Magnum ammo I've shot through these revolvers was almost exclusively with 140 gr or heavier bullets (I think I did shoot one box of 125 gr Remington through the 66 in my intemperate youth). As with most firearms, K-Frame .357 Magnums work best with the ammo they were designed for (158 gr Magnums), but if you start using ammo significantly outside the parameters that the gun was designed for, you're likely to have problems.

The weight of equipment officers had to carry did go up, quite a bit, but the L frame guns didn't solve that. Not a bit. With the same barrel length, the L frame weighs exactly the same as the N frame. They are NOT lighter. They just balance differently and have a slightly smaller (K frame size) grip frame.

The L frame was not a solution to the weight of an N frame, they weigh the same.

This always puzzled me a bit because, while you're correct that most L-Frame .357's weigh the same as a so-chambered N-Frame of the same barrel length, there's no reason why this has to be the case. The reason that L-Frames are so heavy is that the vast majority have heavy barrels with full underlugs while their K and N-Frame counterparts traditionally have half-lug and, in the case of the N-Frames, tapered barrels. While S&W has made a few L-Frames with different barrel profiles like the short-lived Models 619 and 620, they've never made very many for reasons which are unclear to me.

[44 AMP]

I find it somewhat ironic in that, if the bore were leaded by shooting something like standard 158 gr LRN .38 Special ammo, then the old saw of "practice with .38's and carry .357's" might have actually contributed to the forcing cone's demise rather than prevented it. If the shooter you mentioned had shot his revolver exclusively with jacketed .357 Magnum ammo, his barrel would probably still be in good shape.

One of the problems with "old saws" sayings and rules is that, over time important parts get dropped or left out for brevity, or because "everyone knows" and therefore it doesn't need restating.

Things like CLEANING THE LEAD OUT after shooting .38s BEFORE shooting jacketed .357s.

While S&W has made a few L-Frames with different barrel profiles like the short-lived Models 619 and 620, they've never made very many for reasons which are unclear to me.

Nor are the reasons clear to me, either, though someone at S&W must have reasons for them doing what they do. I always felt that if S&W had made the L frame without the full underlug and perhaps with a tapered barrel they'd have a winner, balancing better than the full underlug guns, and being a bit beefier than the K frame, but lighter than the N frame, and having the K frame grip size.

For whatever reasons, they didn't do that to start with, and the models you mention where they did it, didn't last, apparently due to lack of sales, it seems.

[Pumpkin]

A 4 or 5 inch tapered barrel L frame would be worth some significant sucking up to my wife, again

[74A95]

Originally Posted by Webleymkv

Also, the original factory ammo for .357 Magnum was purportedly significantly more powerful that that made today.

This is not true, according to a article in the Shooting Times, May 2023, that looked at the published ballistics of the 357 Magnum since it's introduction in 1935. Todays ballistics are more powerful. This started in 1963 when jacketed bullets were introduced when the 158 grain jacketed bullets were faster (1550 fps, 8 3/8" barrel) than any lead bullets of the same weight listed before then (1510 fps, 8 3/4" barrel). The ballistics reported today of 1235 fps for a 158 grain bullet are from a 4.0" vented barrel, but Remington noted in 1976/1977 that the ammo did not change, just the barrel length.

[44 AMP]

I have seen period data listing the original .357 158 load at 1500, 1510, and 1550fps from the 8 3/4" Registered Magnum.

And I've seen multiple times when different guns shooting the same ammo show different velocities, even as much as 100fps, so I don't consider a handful of fps to be proof of "significantly" more or less powerful, it may simply be the result of different guns giving different velocities.

With my handloads I have pushed 158s over 1400fps from 6" guns and 125s over 1600. One load went 1620fps in one 6" gun, 1670 in another and 1720fps from a third 6" gun.

However, these are my handloads, in my guns, and are absolutely not suitable for general use in all guns chambered for .357 Mag.

[Webleymkv]

I've seen the original 1935-spec .357 Magnum load quoted as 15.5-16 gr of 2400 under a 158 gr LSWC. Every recent (as in the last 20 years) loading manual I've looked in goes no higher than 15 gr of 2400 with either jacketed or cast 158 grain bullets. Also, the original ammo used large rifle primers which, with an equal powder charge, should generate more pressure than the small pistol primers of today's ammo.

While I don't recommend it, I have gone as high as 15.5 gr of 2400 with a magnum primer under a158 gr LSWC only in my N-Frame .357's and, while I wasn't able to chronograph them, the recoil and blast was significantly increased over the factory Federal 158 gr .357 Magnum ammunition I shot the same day from the same gun (4" M28).

[74A95]

Elmer Keith writes in his book 'Sixguns" (1955) that the first 357 Magnum 158 grain loads were 15.3 gr 2400 which produced 1510 fps from 8 3/8 barrel. That speed is the same as what is published in the early catalogs (e.g. 1938 Remington).

In Keith's 1935 American Rifleman article he writes, "the powder charge, which varies with different lots of powder, is approximately 15.4 grains Hercules 2400 . . ." for a speed of 1518 fps.

[bamaranger]

Thanks to 44AMP for correcting my erroneous comments. I had the topstrap/forcing cone issue wrong, and he set the record straight. Also, the L-frames were heavy, in fact, the last issue revolver I carried was a 4'" L-frame and it was heavier than a 4" 629 Mtn Gun in .44 mag.

Wrong on both counts and I freely admit it....once again, I stand corrected.

[jetinteriorguy]

Originally Posted by 44 AMP

One of the problems with "old saws" sayings and rules is that, over time important parts get dropped or left out for brevity, or because "everyone knows" and therefore it doesn't need restating.

Things like CLEANING THE LEAD OUT after shooting .38s BEFORE shooting jacketed .357s.



Nor are the reasons clear to me, either, though someone at S&W must have reasons for them doing what they do. I always felt that if S&W had made the L frame without the full underlug and perhaps with a tapered barrel they'd have a winner, balancing better than the full underlug guns, and being a bit beefier than the K frame, but lighter than the N frame, and having the K frame grip size.

For whatever reasons, they didn't do that to start with, and the models you mention where they did it, didn't last, apparently due to lack of sales, it seems.

The reason I’ve never been a fan of the 686 is I don’t care for the full underlug. I didn’t know they made a 620, now that sucker I’d grab in a heartbeat. I agree a tapered barrel ala. model 27 style would be the frosting on the cake.

[Pumpkin]

My uncle had a nice medium frame (I ?) Colt 38spl that had a scallop shaped machine cut in the bottom of the top strap. I think it was original but I’m not positive. I’m also thinking this was done to avoid unsightly cutting of the top strap? Seemed mostly cosmetic to me or were they thinking it allowed the gases to cool down enough to eliminate the gas cutting?
Didn’t some SAA’s have this done too?

[wild cat mccane]

Drag increases at 4 times the rate of velocity.

The better question is, since that's still only half of even getting to the minimum velocity for rifle level hydrostatic shock level damage, what is your goal that factory FMJ isn't doing?

If you don't have a purpose, which I would argue there is none, it's kind of a difficult question to worry about.

[wild cat mccane]

Also, correct me, but the 158gr wasn't the problem. I thought it was established it is the 125gr Remington load specifically that was causing forcing cone problems.

[Recycled bullet]

It's not the 125 Grain bullets that are eating barrel face.

It's the 22 Grains of hodgdon h110 that's eating the barrel face.

[Pumpkin]

The 110gr factory loads were actually a lower velocity than the 125’s which were the hot rod of the day.
From a 1985 Gun Digest;
110 1295fps 410ME
125 1450fps 583ME
158 1235fps 535ME, all from a 4” vented barrel. Those 110’s were cream puffs compared to the 125’s. My uncle, used to be issued the 110’s and a whole lot of 38spl 148 wadcutters for practice. His carry gun was a 4”66 but was issued a Border Patrol Security Six. He told me the Ruger was too heavy, drug his pants down.

[74A95]

The link 44 AMP posted showed a cracked forcing cone on a gun that had shot no 357 Magnum ammo. And the link I posted in post #2 stated broken forcing cones in 38 Special revolvers.

It's never just one thing (22 gr H110, or only 125 Remington ammo). And it's never just one gun design (S&W K frame 357 Mag).

[Mike Irwin]

"It's never just one thing (22 gr H110, or only 125 Remington ammo). And it's never just one gun design (S&W K frame 357 Mag). "

This. In spades.

Oh, and the reason for the full underlug on the L frame guns?

To deal with complaints that the K frame was too light, and thus kicking too hard, when being fired with full power .357 Mag. ammo.

[Recycled bullet]

110 and 125 Grain bullets use five to seven grains more of h110 or W 296 as compared to 155-170 grain bullets. In small handguns like 357 Magnum this is a lot.

[Recycled bullet]

I have a shot out barrel on my Ruger SP101. I used at least 8 lb of 2400 with 110 grain bullets at 17.5 G per cartridge and at least 8-12 more pounds of h110/w-296 at 20-22 grains each. It looks like an acetylene torch and a sandblaster just ate it up. I shot that gun thousands of times.

[wild cat mccane]

Stated differently to answer the question, I haven't read the new introduced K frames have had any problems. Has anyone else?

[1972RedNeck]

The L frame was not a solution to the weight of an N frame, they weigh the same.

My 4" M65 weighs about 34 oz, my 4" M619 weighs about 38 oz, and my 5" M627 weighs about 44 oz.

I realize barrel lengths aren't the same, but it doesn't seem like my L frame is anywhere close in weight to my N frame...

[44 AMP]

I realize barrel lengths aren't the same, but it doesn't seem like my L frame is anywhere close in weight to my N frame..

Check the specs for the original (full underlug) barrel L frames and you'll see they are the same listed weight as the same barrel length N frame.

I have weighted 4" and 6" examples of both, and with wood grips they are the same or vary about an ounce, due to different densities of the wood in each.

Other, newer non-full underlug barrel L frames are slightly lighter than N frames, but slightly heavier than K frames of equal barrel lengths.

[1972RedNeck]

Check the specs for the original (full underlug) barrel L frames and you'll see they are the same listed weight as the same barrel length N frame.

Hmm, I didn't realize my 619 was that much of a one off. The normal L frames are heavy according to specs.

What's the point of a heavy L frame when you can get an extra round in a similar package (N frame)?