Wear Caused By .357 Loads in Model 19


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ColtShooter
December 11, 2003, 12:34 AM
I just started loading .357 for a 6" Model 19. I've read that hot 125 grain loads cause forcing cone erosion and flame cutting. I've also read that 158 grain loads are gentler on the gun. I'm trying to reconcile these ideas.

Are hot 125 loads bad because there is lots of hot gas escaping after the bullet leaves the case, therefore causing erosion at the front of the cylinder?

Are 158's gentler, because at normal pressures the gases are initially confined to the case, since 158's are harder to get started moving?

I would have thought that 158's would cause more wear on a gun because they would create more recoil and stress on the frame, but maybe that's not the case.

What role (if any) does the pressure of the load have on wear?

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stans
December 11, 2003, 07:02 AM
I think the lighter bullets cause problems due to not only the volume of hot gases but also the velocity at which the lighter bullets impact the internal surface of the forcing cone. The gases will erode the cone and possibly cut the top strap, but the thin spot at the bottom of the forcing cone can be cracked by the high velocity rounds.

ColtShooter
December 11, 2003, 09:52 AM
I hadn't considered that aspect at all. Yet another variable!

Old Fuff
December 11, 2003, 10:10 AM
For "everyday" shooting at the range and such I suggest you load top-end .38 Special loads in the slightly larger .357 case. Use lead bullets because they are easier on the bore. Use factory jacketed loads for serious carry and occasionaly shoot a few for practice. This is what the model 19 designers had in mind in the first place.

Quantrill
December 11, 2003, 11:01 AM
I keep hearing about the "K" frame being shot loose or damaged by full load .357mag. Maybe it is so but in my 50something years of shooting, I have personally yet to see one. Quantrill

Wil Terry
December 11, 2003, 12:02 PM
They are about equally divided between 38SPL and 357MAG cartridges.
The ONLY problem I've ever had with this pistol was shooting the gas ring loose at round 39,101. S&W fixed it gratis and it was out of my hands for a week. This is NOT a problem at all with the newer M19's as they went to a different gas ring system.
The forcing cone shows wear for sure but this M19 4" is still the fastest 4" 357 sixgun I've ever chronographed; never had a 6" one faster including 3 Colts, a bunch of Rugers, and all the test guns over the past 30+ years.
Tis my considered opinion the M19's reputation for wearing out quickly is bullshiq. I hope I live long enough to wear this one so I can toss it in the trash and go buy a new one.

GooseGestapo
December 12, 2003, 03:18 PM
Coupla' things to consider;
Most of what Terry M. said I agree with.

Rather than being "wed" to a single gun, I've crossed paths with a number of .357 K-frames.

IMO, the problem with the wear issue was due to some really hot ammo produced from the early '70's till the mid to late '80's, when a lot of .357 ammo began to "cool" down at the factory level...
It was found that a lot of the "hot" ammo, particularly the 125gr JHP loads were producing well over 50,000 psi when the technology became available.

SAAMI specs have been lowered somewhat for the .357, and the "wear" factor on the K-frames is largely "lore" now.

I have seen some top straps "flame cut", forcing cones split-and/or eroded.
These were L.E. range guns used for training/testing/qualification purposes and often the described "problems" were the result of over 50,000 rounds fired.

I had a 686 (m)4" (an L-frame); (first issue with "recall" stamp added after modification- (hammer nose replaced- primer cratering due to those loads I mentioned!).
After ~50,000rds, approx. 3,500rds of Magnum- (rest .38spl), at least 800 of which were the 125gr.JHP Winchester at 1,450fps (chrono'd!). It had erosion of the forcing cone that was noticeable if examined. I set the barrel back 1- turn, and recut to 11deg. It was still "tack driving' and capable of "winning" an NRA service gun match, of which it did numerous times. It had approx. .005" of flame cutting.

K-frame battering is not as "big a deal" as those who want to talk it down prefer.

With current SAAMI max and using some of the faster burning powders... such as BlueDot, and even Alliant 2400, you'll probably never see problems. (Max load of H2400 in '70's was 15.5gr, with some loading 16.0!-current favored load is now 14.5), I've seen 21.0gr of Win296 being loaded under a 125gr Zero JHP on an "automatic" loading machine!! <not at Zero,Inc.>)

Even if you do have problems, like with Terry's gun, it'll probably either be warrantied, or fixed cheaply.
The erosion issue is greatest , for the reasons others mentioned, with large quanities of relatively slow burning spherical powders and high velocities, and light bullets. The forcing cone splitting is largely due to heat stress and alteration of the heat treating (becoming brittle) combined with the hardness of the jacket material. Seldom if ever seen where heavy lead bullets are used.

The flame erosion of the top strap usually stops after a depth of ~.010", and I've never seen one that was cut to where it was unserviceable. A range gun I was shown once had over 100,000rds through it; had been rebarreled, and previous barrel set back till it was unserviceable, and had the .010" gas-cutting, and was still "On the job".

If you like the feel, and size of the K-frame, get it....


Thats what the K-magnum's all about. It'll do for most any purpose you might put it too.

ColtShooter
December 12, 2003, 07:08 PM
If you like the feel, and size of the K-frame, get it....

I've got it! It came up used and I had to have it. It's in like new condition from '71 and I wanted to find out how NOT to tear it up.

The last .357 I had was around 1980 and from what I'm hearing, there was a reason that ammo was abusive to shoot.

Thanx for the very detailed response.

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