158 vs 125 Gn SJHP

K

KnotRight

New member
After doing some reading on 357 Mag loads, it seams that shooting the lighter weight bullet in a K frame S&W can cause problems with the frame.

WAY back, I had a Colt Trooper, Colt Python, Ruger Single action and current have a S&W 66 and 686. Just got the 686 but had the 66 for many years. I never knew or even dreamed shooting lighter loads in the 66 could damage the frame. Back in the 70's I reload all my bullets and what I have written on the cases the feet/second is around 1250.

The 66 have not been shot in years (switch to pistols) but getting back into wheel guns. Has anybody had any problems with the light weight mag loads that are shot in the 66.
 
I have never experienced any problems with any .357 Magnum loads in any of a number of revolvers. And most of my guns have right at, or above, 10,000 rounds fired through them.

Bob Wright
 
After posting this topic, I started thinking about the loads that I loaded, used and still have:

110 SJHP 16.0 Blue Dot 1600 F/S
125 SJHP 7.5 Unigue 1250 F/S
150 SJHP 8.0 Unique 1200 F/S
150 SJHP 6.0 Bullseye 1150 F/S
125 SJHP 10.0 Unigue 1500 F/S

I have not reloaded in 15 years and wondering if the above powder is still used. Also do you think the above loads are OK to use in the 66 with the 2 1/2" barrell.

Most of the rounds shot have been wad cutters in 38 casing.

Another load that I liked was a hollow based wad cutter that I inverted when I loaded it. Not for target shooting but a great round for home defense. The soft lead would make one big hole.
 
I believe the problem was with the forcing cones, not the frames. Using slow burning powders in attempts to push short light bullets meant hot gases escaping around the bullet causing excessive erosion.
 
I've looked into this issue and opinions vary as to cause. I've heard damage could result from lightweight bullets used with slow burning powder. I've also heard it was due to the lesser amount of metal at the 6:00 position of the forcing cone and only after many thousands of rounds. One former LEO told me he had only seen it in K-frame revolvers used by recruits for training.

I was also told that the magnum 125s hit the forcing cone faster than heavier bullets and thus destroyed the forcing cones. Because of this Smith and Wesson said to only use 158 grain mags since they start slower.

I don't know why it happens, when it happens. So I shoot only mid ranged ammo in my K frames. I save the heavier stuff for the N frame 357s.

That said, 10 grains Unique sounds pretty stiff for a light weight framed 357. That's what the K frame is. Designed to be shot with 38 special velocities and carried with 357. Bill Jordan was the fellow that came up with the concept, IIRC.

images
 
Large amounts of light grain, high velocity with slow burning powder such as H110 will pound any revolver and the results could be erosion of the inner forcing cone faster and faster flame cutting on the top strap. Any revolver could develope this eventually. Here is a picture of a GP100 with a cracked forcing cone and a lot of erosion of the forcing cone. This GP100 had its barrel replaced at Ruger. The round was Hornady XTP over 22 gr of H110 with Remington 512 primer. This person shot 100 rounds a week for a year with this result. If a person loads there ammo, one has too be careful and not go overboard. Personally, I stay away from light grain ammo and shoot 140 gr or higher even in my large frame black hawk 357 magnum.
Just opinion.
Howard
GP100HornadyXTPover22grofH110withaRemington512primer.jpg
 
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The round was Hornady XTP over 22 gr of H110 with Remington 512 primer.
Click to expand...

Depending on the bullet 22 grains is listed as starting for the 110 grain bullet and is WAY over max in a 158 grain bullet.
 
the gun is almost always goign to be factory set to a 158 grain bullet.

magnum itself in the handgun world means, "standard, or above standard weight projectiles at higher pressure and velocity"
 
The Hodgdon reloading manual lists that as a max. That is a lot of abuse using the 125 in a 357
Click to expand...
That is my point. One has too watch there reloading manual and not go to the max. A lot people try to test a revolver to the max. This is a GP100 so even the "built like a tank" Ruger will wear out sooner when a person goes too far.
Like I said, stay with the heavier weight round.
Regards,
Howard
 
This is the best analysis of the issue I've ever found:

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

Personally, I stick to either .38 Special ammo or .357 Magnum ammo with bullets of 140gr or heavier in my K-Frame (Model 66-2) and reserve the lighweight magnums for my N-Frame (Model 28-2). To me, it's not really that big a loss as I actually prefer the 158gr loadings anyway due to their deeper penetration and reduced flash and blast as compared to 125gr and lighter loadings. My typical .357 Magnum self-defense loading is Remington Express 158gr SJHP and my normal practice load is a 158gr LSWC over 14gr of Alliant #2400 with a Winchester small pistol primer.
 
A little history and hopefully a little sanity...

The problem first showed up in S&W model 19s, because of their specific construction, and their widespread use, particularly by police.

Flame cutting of the topstrap (a minor concern, but found to be a self limiting problem) and cracked forcing cones (a serious issue), started showing up at a much higher than normal rate, after general widespread use of the 125gr JHP loads became common.

Now, the 19 had been in service for quite a few years, and was a real jem for uniformed officers who had to wear it for hours at a time, and use it seldom. It had its share of issues when overused, like any revolver in its class, but nothing really out of the ordinary.

Until the hot 125grJHP defense load became popular (for good reason), and they began seeing regular use with this level of load. A light (for caliber) bullet, and a heavy charge of a slow buring powder turned out to be not very good for long life of the forcing cone. Lots of theories about exactly which part of the combination was most to blame, short bearing surface, large hi speed hot gas, etc., were blamed.

Seems it wasn't a single thing, but the combination of things, including the model 19 specific design, which were the problem. ALL revolvers can suffer this fate, if a certain load is shot enough. What varies is what load it takes to do it, and how many of them the gun can take.

Its not just light bullets, guns with lots of rounds of the 110gr and no significant use of the 125s don't seem to be as much at risk. But the factory load for the 110s is different than the self defense loaded 125s.

19s and others shot 158s for a long time without abnormal problems.

That Ruger was certainly overstressed. The Hornady manual (3rd edition, the first one I grabbed) says max is 20.8gr H110 with that bullet. And that was in a Model 27!!!!!!

5000+ rounds he shot, well over at least one book max! I wonder if he was surprised when trouble showed up?

Any idea of what velocities that load with giving?
 
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