S&W Model 19 (K frame magnum) longevity

[curioushooter]

I recently aquired a model 19 and really like it. I have read up on the forcing cone cracking issue, but am not sure what to make of it really. For example all the "weak parts" of the design are in fact much beefier than the J frames, which are also in 357 and often used with 125 grainers. 357&44 mag were both downloaded in the mid nineties, the time when the J magnums were introduced. My thinking is that if I keep my loads to the 35k PSI max of today, or less, the model 19 should last a very long time, as it was designed to accommodate the full powered 40k+ pressures of loads in the 1950s. I am not sure I want to stoke it maximally anyway. I can already tell the recoil is noticeably more severe than with my 686. Just curious what others think and what your loading strategy is if any.

[M-Tecs]

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

[onelight]

The 19s are a great carry gun but if I wanted a range gun to shoot a lot of 357s I would pick a heavier gun it's not just the barrel issue you mentioned the cylinders will shoot loose , excessive end play is the result quicker than some heavier 357s they are a classic smith model but I would shoot 38 power loads with a few 357s on occasion , and carry 357s when needed.

[tazman]

Take a look at the bottom of the forcing cone right in front of the cylinder. There is a small flat spot there, at least on the older models. That is where they crack.
I had one crack there back in the late 70s.
There are a number of reason given for this that you can find online.
I just acquired another one recently. It will be fed 38 special unless there is a special need since I do have a 686 that doesn't have the cracking issue.
I love the way those K frame Smiths handle.

[reddog81]

What dash is your model 19? How much do you shoot?

It’s the 125 grain bullets loaded to the max with certain powders that’ll cause forcing cone issues. Avoid that combination and you’ll be fine for a long time.

[Hrfunk]

My 2 1/2" Model 19, and my 3" Model 66 have both digested a fair number of full-power 158 grain .357's without issue. I tend to avoid the 125 grain magnums since those were the ones most related to the cracked forcing cones. Interestingly, in the 4" M19 I used in my last video (my wife's revolver), I tend to prefer 158 grain .38 +P ammo. It's softer shooting than the magnums, but it still packs a wallop at any reasonable handgun distance; AND it's easier on that fine revolver.

Howard

[Petrol & Powder]

curioushooter - 1. you're making some false assumptions and 2. this is a well established but not well understood topic.


Starting with the statement: " 357&44 mag were both downloaded in the mid nineties, the time when the J magnums were introduced. My thinking is that if I keep my loads to the 35k PSI max of today,"
That's not entirely true. The SAAMI pressure limits for 357 and 44 mag (35K & 36K psi respectively) were not changed in the mid nineties. The methods used to measure pressures were changed over time (copper crusher vs. psi measurements via strain gauges and other systems) .

Comparing a K-frame to a J-frame and saying the K-frame must be stronger is also a bit flawed. Yes the K-frame is a larger frame but the failure point deals mostly with the barrel shank that protrudes from the frame and the spacing of the chambers from the center axis of the cylinder. So in some regards, the J-frame may actually be stronger in those areas.

Your statement, "the model 19 should last a very long time, as it was designed to accommodate the full powered 40k+ pressures of loads in the 1950s.
"
..is also a bit off. The model 19 was NOT designed to handle "full powered 40K+" loads, "of the 1950's". It was designed to handle some use of magnum loads and those loads were not 40K +psi loads.

OK, moving on now. The history of the magnum K-frames is well known. Bill Jordan was instrumental in convincing S&W that a magnum capable K-frame was needed and S&W came up with a way to make that happen. I can't really blame S&W for that over-reach. I think they looked at the concept and said, "yes, we can make this work". I don't think the magnum K-frames (models 13, 19, 65, 66) were ever intended to shoot magnum loads exclusively. In any event, the magnum K-frames were reasonably durable when fed a moderate diet of 158 grain bullets at magnum pressures. Problems began to show up when magnums were used exclusively in the K-frames and the shorter 125 and 110 grain bullets were loaded in magnum cartridges.

The K-frame (M&P) was a 38 Special design, and in hindsight, that was about the limit of that platform. The spacing of the chambers and the location of the center axis of the cylinder requires a flat to be cut in the barrel shank at the 6 O'clock position. This weakens the barrel at the forcing cone. It is no big deal at 20K psi and it can even handle the 35K magnum loads for a little while if the 158gr bullet is used.

Beyond the forcing cone issues, the magnum K-frames also suffer from some frame stretching and end shake issues when magnum loads are used for long periods of time.

The bottom line is the K-frame was never really a good platform for long term use of magnum rounds. Like the infamous "A Bridge Too Far", the idea of a magnum K-frame was just a little too much to ask of that platform.

Ruger knew this when they came out with their Service-Six and other DA Six series revolvers. Those Ruger's were about the same size as the S&W K-frame but they were designed from the beginning to be true magnum level guns. S&W finally acknowledged their over-reach when they introduced the L-frames (581, 586, 681 & 686). The L-frames were not much larger than the K-frames but the L-frames were true magnum guns from the beginning. The L-frame is what the magnum K-frame should have been from the beginning.

So, can a magnum K-frame be shot with magnum loads without damage? The answer is, "sort of".
With moderate use of 158 gr bullets and magnum loads, that model 19 and other magnum K-frames will give good service. I do think that even in moderation, those magnum loads will result in excessive end shake sooner than when used with 38 Special loads.
With the short 125 grain and 110 grain bullets in magnum cartridges you will see a cracked forcing cone in short order. I've seen it. I'm not talking out of school, it's real thing! How soon will the cracking appear? That's harder to say.

[Outpost75]

The K-frame .357s were never designed to last with a steady diet of full-charge .357 Magnum loads. Back in the day the Model 19 came out the usual practice was for police to use standard pressure .38 Special for practice and qualification, but the Model 19 could stand moderate duty use of .357 ammunition. The gun was not intended to exceed a ratio of 6:1 of .38 Special to magnums, and that being only when the gun would be touched by a factory-trained armorer on an annual basis to make adjustments necessary to keep the gun in proper time and adjustment.

By the 1980s police training and doctrine had evolved to require officers to qualify with the same ammo they carried on the street. This resulted in greater wear and tear and shorter service life of the guns. The Model 19 was no exception and recommended practice was not to exceed a 50-50 ratio of standard pressure .38 Special to +P service loads. Standard pressure ammunition was still used for practice, but duty ammo used for actual qualification. Use of .357 ammunition was still recommended not to exceed the 6:1 ratio of .38 Special (combined of all types) to .357s.

It is normal for a K-frame .357 to develop end-shake after about 1000-1500 rounds of magnum ammunition. When end shake reaches about 0.002" the crane arbor would be stretched and adjusted to remove the end shake. This can only be done twice before cylinder gap opens to the service maximum of 0.009". At that point either the barrel must be set back (common gunsmith fix) or a (+) cylinder fitted (usual factory fix) to correct the condition. Usually by this time the cylinder will not carry up correctly in DA fire, and a wider hand is fitted to correct the DCU (doesn't carry up) condition. If the locking notches in the cylinder are also peened, the cylinder stop will be replaced with an oversized one.

Later Model 19s had a small flat machined on the barrel extension at the 6:00 position to clear the gas ring on the cylinder. The cylinder gas ring was moved from the yoke onto the cylinder of later guns to mitigate cylinder binding with use of the Winchester X38SPD all-lead hollowpoint +P .38 Special ammunition (FBI Load). "Hubbed cylinder" guns are not recommended for frequent use with full-charge .357 ammunition. This is because if shot frequently with full-charge .357s the barrel extension will crack through the thin section where it had less heat capacity. Older Model 19s having the gas ring on the yoke, rather than on the cylinder, do not have this problem, but after about 5000 rounds of full-charge magnum ammunition will require both a long cylinder and oversized lockwork parts to stay in specs. Once a gun reaches this point, if it again goes out of time or develops further end-shake, it already has all the oversized parts in it. Factory practice is not to attempt further repair of an OFG (open front gage the factory term noted on the repair-reject tag) and return the gun because no repair parts are available.

Department guns tagged OFG and returned are scrapped.

In extensive testing by US Customs and Border Patrol at the Federal Law Enforcement Training Center in Glynco, GA, it was determined that the K-frame .357s would not pass a 5000 round endurance test of full-charge .357 without malfunctions or requiring replacement parts that required maintenance above the user level.

Attachment 246738Attachment 246739Attachment 246740

The Winchester .38 Spl. +P+ 110-grain Q4070 Treasury load was developed to improve handgun duty performance, but its higher chamber pressure of up to 23,500 psi caused excessive wear & tear on the guns, especially the forcing cone cracking issue. Repeated failures of K-frame .357s in CBP service led to development of the L-frame.

If you want a revolver which will handle a steady diet of full-charge in a volume of 5000+ rounds of .357s or +P+ LE .38 Special loads, without malfunctions or requiring parts replacement, buy an S&W Model 20, 27, 28, or modern L-frame, Ruger Six series 160- prefix or later (Mil-Q-9858A), GP100 or Colt Python.

[Petrol & Powder]

/\ Thank You, Outpost75

[Der Gebirgsjager]

Good post, Outpost75.

[curioushooter]

Thanks for the responses, though there is more to the pressure REDUCTION in the mid nineties than simply changing methods of measurement, though that did indeed occur. I've called or written every major powder company, including Vitavouri, which required the use of a translator (and they use a different method, CIP's, to measure pressure which is why some of their loads are HOT compared to SAMMI stuff. In 357 in particular some of their starting loads considerably exceed MAX loads when tested by SAMMI methods).

This is trivially demonstrable: max loads in of powder and bullet combinations before and after that period were reduced. Speer manual #12 discusses the point and contains both data where the test revolver was a M19 at 35K PSI and "silhouette loads" where a Contender was used at much greater pressure. Example: Lyman 47th (this is pre-reduction) lists 17.7 grains of H110 with a 158 grain Hornady XTP at 42,000 CUP. Hogdon lists the 158 XTP with H110 at 16.7 at 40,700 CUP. If you look at newer Speer data (using the 158 grain JHP) it's 15.5 with H110 (I've called Speer this was tested in 2018 by modern SAMMI MAP at limited at 35KPSI). Not the same bullet but similar. Sierra lists it at 16.3 with their 158 JHP. Hornady lists it with the identical bullet as Lyman 47th at 15.6 grains max (I've called them, I forgot when they tested this but it is at the modern reduced SAMMI recommend max). All of these loads used magnum primers. This represents two grains of powder reduction in the top load, or about 12%, meaning old starting loads often exceed contemporary max loads. The upshot: these are not full charge magnums anymore. And to be honest full charge magnums have problems like extraction that car be obviated by backing off a little. Those ultra high speed flyweight loads using heavy charges of slow, hot burning powders appeared to have been abusive. And they are still abusive when you put them in a larger revolver, it's just that it wont suffer as noticeably or quickly.

My point is that there was a genuine reduction in power level. It so happens this transpired at the time (~1995) of the introduction of the J magnums. Make of that what you will, but I have a J mag (a 60-18) and a dial caliper. J frames are less beefy in every dimension but one: because they are 5 shot their cylinder stop cuts are made between the chambers instead of over them, so K frames have less metal between the chamber at this point. But I've measured everything else. The Top strap, frame, crane, barrel, cylinder walls (very nearly identical), etc. are all larger. Even at the 6 o'clock position a K (19-3) frame's barrel is thicker than a J frame's barrel. The L (686-6) and N (28-2) larger still (though chamber walls on the 7-shot L frame are very nearly identical to the J and K frame). There is no doubt the L and N are stronger in my mind. Though it is surprising to me how little bigger the L frame is.

Another thing. The Model 19 and 29 came out the same year, both employ the same sound idea: use a higher pressure cartridge than the parent cartridge in the same sized frame using improved metallurgy to sufficiently strengthen the firearm and therefore delivering a small for power level revolver, making it more bearable to carry but sufficient to do a wider range of jobs. The real problem is that some people can never be satisfied and always seek too much of a good thing until it surpasses the physical limitations. This was something I struggled with until I realized how counterproductive it was.

I still stand by my reasoning that if a J is strong enough for properly loaded ammo than certainly the K frame should be as well as it is bigger is all dimensions but one and was designed at a time when the ammunition was higher pressure. I suspect problems arose in K frame because it was subjected to ammo that turned out far more stressful AND shot more frequently than it should have been. Take away either the excess stress or the excess frequency or BOTH and it should last. Basically stick with modern starting loads. But all this shoot it with 38 Special sounds like a gross overreaction. The things were proofed at whatever 357 magnum is proofed at. It says 357 Magnum on the side (mine does at least). It's not the platform to use for pounding away with uncle Earl's pissin' hot handloads no doubt, but that is not what K frames are all about IMO.

[alamogunr]

It's obvious to me that the two of you were typing your posts at the same time. Very interesting! Lots of good information in both posts and very little overlap.

I don't use .357 mag loads in my Model 19 so I'm not particularly concerned except I bought it used and I don't know what the previous owner did. I guess time will tell.

[El Bibliotecario]

After nineteen years of shooting a Model 19-3 with 13.5 grains of 2400 and Lyman 358156 bullets, the cylinder axis pin elongated to where I had difficulty opening and closing the cylinder, necessitating the axis pin's replacement.

Since I have yet to damage the forcing cone I am apparently doing something wrong.

[Outpost75]

What must be considered with K-frame and J-frame S&Ws in .357, as well as the newer L-frame .44 Magnums, is that none of these had as their "design intent" to withstand high volume use of full-charge magnum ammunition.

S&Ws marketing research presumes that civilian hobby shooters will shoot relatively few magnum loads, and upon finding them unpleasant to fire in their compact, light-weight gun, once their curiosity is satisfied, will use only a few, and from then on do most of their shooting with standard pressure and moderate level +P loads, in a 50-50 ratio which the gun can stand. In civilian hobby use, the manufacturers are banking on that assumption that few owners will shoot the guns enough with full-charge magnum loads to "wear them out."

The serious high-volume "gamers" and others who "love the bang" should not choose a K- or J-frame .357 in planning to shoot it alot, if they want it (and their hand) to last.

[Outpost75]

After nineteen years of shooting a Model 19-3 with 13.5 grains of 2400 and Lyman 358156 bullets, the cylinder axis pin elongated to where I had difficulty opening and closing the cylinder, necessitating the axis pin's replacement.

Since I have yet to damage the forcing cone I am apparently doing something wrong.

The center pin was not hardened on earlier K-frames, so its end normally gets peened in heavy use. A common gunsmith repair method is to disassemble the cylinder and to simply stone the burr off the muzzle-end of the center pin, and reassmble. The factory recommendation is to replace the older soft center pin with a hardened one.

Pre-1980 Ruger Sixes had the same problem.

[Char-Gar]

Bill Jordan was the spirtual father of the Combat Magnum/Model 19. He called it "The answer to a peace officers dream". The first one I saw, handled and shot came out of Bill Jordon's holster one hot day on the Rio Grande River about 1958.

I was plinking at a bend in the river near the old smugglers crossing of Las Prietas. Jordan and another guy rolled up on me in a Border Patrol Jeep. I was using the Republic of Mexico as a backstop and Jordon saw my tire tracks going to the river and follow the tracks to see what was up. They found a kid plinking with a Smith and Wesson K-22.

Jordon decided to join me in the plinking session and unloaded his Combat Masterpiece and reloaded it with factory wadcutter target ammo from his Jeep. He reloaded it with full snort hadloads before returning it to his holster.

This is just to confirm what Outpost 75 said. The pistol was not designed for a steady diet of full snort magnum loads and the original user knew that. As we get farther down the corridor of time, folks forget the past and the lessons learned.

If I want to shoot full snort 357 Mag loads, which I don't often do, I will turn to my 1972 3 screw Ruger Blackhawk.

[Der Gebirgsjager]

Something not yet touched on -- changes in heat treatment and alloys. Today we have .357 Mag. "J" frames, but to bore out a J frame of the '60s to .357 Mag., or to load it to .357 Mag. power levels would be creating a hand grenade. Also, the modern "Classic" series of S&Ws including the 19 are doubtless more durable.

[onelight]

The center pin was not hardened on earlier K-frames, so its end normally gets peened in heavy use. A common gunsmith repair method is to disassemble the cylinder and to simply stone the burr off the muzzle-end of the center pin, and reassmble. The factory recommendation is to replace the older soft center pin with a hardened one.
Pre-1980 Ruger Sixes had the same problem.

I had to do this on my mod.29 I have had since the 70s it's been fed mainly 250 grain Keith bullets at 900 to 1000fps probably 10 to 1 with 240gc on 25grns. Of 296 it also developed excessive end shake I have no idea total round count in 45 years , a bunch . Stoned the center pin , shimmed the cylinder still a great shooter.

[Outpost75]

Something not yet touched on -- changes in heat treatment and alloys. Today we have .357 Mag. "J" frames, but to bore out a J frame of the '60s to .357 Mag., or to load it to .357 Mag. power levels would be creating a hand grenade. Also, the modern "Classic" series of S&Ws including the 19 are doubtless more durable.

To a degree this is true, but the civilian small-frame .357s of today are still not engineered to law enforcement durability standards.

[El Bibliotecario]

The center pin was not hardened on earlier K-frames, so its end normally gets peened in heavy use. A common gunsmith repair method is to disassemble the cylinder and to simply stone the burr off the muzzle-end of the center pin, and reassmble. The factory recommendation is to replace the older soft center pin with a hardened one.

Pre-1980 Ruger Sixes had the same problem.

At nineteen years per axis pin, I hope I have the opportunity to replace it at least one more time.