# 357 v K Frame What Fails?



## FHBrumb (Oct 27, 2007)

What does the 357 round "do to" the K Frame?

How much hard ammo does it take?

I really like the 65, but I'm not clear on those questions.

Most of what I'd shoot would be 38spl standard pressure. If I plopped a few 357s in there from time to time, what am I doing to the revolver? Let's just pick the number of 200 38 rounds a month and 24 rounds of 357 a month. Am I killing my 65, or is that level of use no issue?

Factory loads, but stout ones for 357. Paper poppers for 38spl.

If the K Frame seems like a bad deal, I'm thinking the SP-101 would be a better choice. Three inch 357s are tough to find, and I just need one bad...


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## TOF (Sep 7, 2006)

I don't know about your 65 but with a GP100 you can shoot what you want when you want and not worry about it staying together.

tumbleweed


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## FHBrumb (Oct 27, 2007)

I'm in the process of shopping. The SP-101 is an easy find with the 357 and 3 inch barrel for about $479. The 65 can be found online for just over $600. The extra one round in a small package is the attraction.

I'm just not certain what gives up on the K frame Smith, and what it takes to make it give up. I've just read over and over that the 357 was "the demise" of the K frame. Does it take 5,000 rounds of 357, or 500? 

It will likely be the SP-101 in reaility. I almost snagged one this week, but the one in the case was pretty badly scratched up for a new revolver. I asked twice if the sales dude was sure it was new... 

I'm just partial to the Smith revolvers... If there was a fixed sight 357 Model 60 with a three inch barrel, there would be no problem.


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## rx7dryver (Jan 17, 2007)

The problem if I remember correctly was that the forcing cones would wear prematurely and crack. I do not know how many rounds it takes. I would think at 24 rounds a month it would take a while.


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## DJ Niner (Oct 3, 2006)

FHBrumb said:


> What does the 357 round "do to" the K Frame?
> 
> How much hard ammo does it take?
> 
> ...


It's kinda like asking when your car engine will die if you change the oil every 20,000 miles instead of every 5,000; there's no specific answer, but it almost certainly will die earlier than the better-cared-for vehicle.

The primary problem with heavy magnum use in the K-frame magnums seemed to be cracking in the forcing cone area. These guns were designed and fielded as a lightweight-but-more-effective-than-a-.38 sidearm for police, when standard department policy was qualifying with .38 Specials and carrying magnums, or perhaps only shooting a few magnums semi-annually or annually. Under these conditions, the K-frames lasted longer than most police departments needed, so the cops were happy enough. When liability concerns drove qualifications to more rounds, fired semi-annually or more often, and officers were required to qualify with the magnum loads they carried on duty, the guns started to suffer and failures became more common. Even then, many guns went for decades with no problems, while others choked or broke in the first few years.

Here are a few photos of a cracked forcing cone in a S&W model 19 K-frame Combat Magnum. The history of this gun is unknown, as is the total round count of what type(s) of ammo was used in it. The little flat spot machined on the bottom of the forcing cone, required for clearance when the cylinder was pivoted into the frame, seemed to be the weakest area, and so most cracked forcing cones are similar to this one (in location, if not severity).




























There were also other occasional problems with small-frame magnums, things like broken hammer and trigger pins, excessive timing wear, and once in awhile, a stretched frame (pretty rare, I understand). None of these were ONLY seen on K-frame magnums; heck, I've seen K-frame .38 Special M15s break hammer and trigger pins on a steady diet of +p .38 loads.


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## FHBrumb (Oct 27, 2007)

Excellent explination. Thank you.


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## wjh2657 (Jun 18, 2008)

The K-Frames were designed pre 1900 to be used with .38 S&W. They made the transition to .38 SPCL with changes in metallurgy. They were and are excellent .38 SPCL revolvers. I still own a S&W M&P Revolver made in 1951.

When S&W first came out with the .357 Magnum in revolvers, they brought it out in the larger and heavier "N" frames. These were rugged guns built for .45 LC and .44 Spcl and very capable of handling the hot .357 Mag's abuse. They actually had already chambered the gun for the .38/.44 "super .38" and were ready for the .357 Magnum.

Bill Jordan was _the_ gun "guru" during the sixties and talked S&W into building a.357 Magnums on the K Frame for service revolvers. They were lighter, quicker and very accurate. They also were still a .38 Spcl revolver shooting the .357 Mag round. They didn't hold up to long term use of the .357 Magnum.

Elmer Keith, another "gun Guru" during that day, still preferred the N-Frames for Magnum use (although he specialized more in the .44 Mag)

The Rugers that came later were rugged little "tanks" built from the ground up to withstand the .357 mag. In this generic size (K-Frame) they are the better bet for .357 magnum use. I prefer the S&W 686, another, albeit larger, gun designed speciically for the .357 mag.


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## FHBrumb (Oct 27, 2007)

Good info from all. I'd be one of those guys rarely shooting a magnum load. I'm trying to get a Model 65 with a 3 inch barrel over on GB. If I can't get one, I'll go with a new SP-101 3 incher...

Thanks again for the info.


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## FHBrumb (Oct 27, 2007)

Snagged a 3 inch Model 65 at GB for a reasonable price. If I feel the need to pound out a few Magnum rounds, I'll keep the count down. Mostly, it's a 38 to me...










I also got a few goodies to work with.
New style thumb latch.
Wolff spring set.
Secret Service style grips.









I'm very tempted to send the cylinder off to TK Custom for a full moonclip conversion. and if I tripped over a 3 inch Ladysmith contour barrel, I might be tempted to snag it too...


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## wjh2657 (Jun 18, 2008)

I have always considered my K and J Frame S&W .357 guns to be "extra sturdy" .38 +P guns. I prefer the weight of an L frame or N frame when firing .357 Magnum ammo.


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## FHBrumb (Oct 27, 2007)

I also looked for a 3 inch 681, which would have been fine. I never saw one without porting, which to me is undesirable.

In the end, I wanted one of several guns. This was the last one voted off the island. I'll shoot a ton of 38 from it, with the occasional 357.


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## DJ Niner (Oct 3, 2006)

Great choice! I had a 3" M13 (same gun, in blue steel) a long time ago; should have kept a tighter hold on it, but I let it go in some seemed-like-a-good-idea-at-the-time trade. It shot and carried very well.

Under the circumstances you described, your new acquisition should last a long time. Good luck and good shooting!


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## FHBrumb (Oct 27, 2007)

Is it just that the pressure is too much for the weakened (flattened) part of the forcing cone? Looking at the crack you showed, it looks like the cone might slightly expand during firing, as the crack ( or tear) is length wise. Would lead versus jacketed then damage it less? 

Is is something else? Does the "fire" behind the bullet erode it, and that's just where it shows first?

Some folks say it has something to do with light bullets. How can a 110 damage it, but not a 158?


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## DJ Niner (Oct 3, 2006)

Flame erosion may have a part in it, as this does remove tiny amounts of metal with every shot. 

The lighter bullets accelerate more quickly, so they slam into the forcing cone at higher speeds than the heavier bullets; plus (due to their shorter overall length) they are more likely to be slightly cocked or off-center when they jump the gap than a longer 158 or 180 grain slug, which can further stress the forcing cone area. The full-power 125 grain loads are also particularly vicious pressure- and recoil-wise; they slam those poor lightweight .357s around pretty hard on ignition.


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## FHBrumb (Oct 27, 2007)

Sounds logical. If I choose to shoot loud ones, I'll stick with the big boys. No 110s and no 125s.

I'm a heavy bullet kind of guy anyway.


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## R.J.Adams (Apr 10, 2008)

Nice wheelie to say the least. I bet you are very happy in the long run. With a little common sense she should give you years of trouble free service. Be sure to post a target or two,R.J.


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## Teuthis (Apr 9, 2008)

In Vietnam I shot thousands of rounds through model 19's. They eventually will "shoot loose"; that is the cylinder notches that the hand locks up, become widened and the cylinder has too much play in it. But that takes a lot of rounds. We were not shooting light bullets though. The 125 and 110 grain rounds, very high velocity, can damage the forcing cone. But overall, with 158 grain rounds it is primarily that the cylinder lockup becomes loose. There is also some stretching of the frame eventually; but the weapons remained servicable for long periods. 

I think one can shoot many rounds through a K-frame .357 with no concern. I still have a Model 65 that I carried in the 70's and it is like new after a moderate number of rounds over the years.


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## FHBrumb (Oct 27, 2007)

Thanks for the info.

My 65 is a project gun. I have done some work already, but have more to go.

Phase one of the work:
Right now, it has new Wolff Springs, and an internal buff to reduce friction. I changed out to a new style thumb latch. Then I started to buff it out. I scrubbed with 800 and then 1000 grit wet/dry and then hit it with the Mother's Metal Polish. The cylinder is at TK Custom for a full clip mod. I also get my grips on there. It's so bright, it's difficult to take pictures of it...


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