What IS a "full power" .357 magnum load?


10 Ringer'
September 27, 2003, 11:15 AM
I was reading into the design history of S&W "K" versus the beefer (true magnum-worthy) "L" frame and it was said that the K frames couldn't take a regular diet of full power magnums and was thus born the heaver L frame. At least as my shooting experience goes, the .357 magnum IS the full power descendent of its .38 special/+P family line. What am I missing here? Are there actually "light" magnum loads... and is that by bullet weight or powder load?

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Mike Irwin
September 27, 2003, 11:43 AM
.357 Magnum loads have actually gotten somewhat wimpier over the years.

The original loads developed by Winchester for S&W were some smokers.

September 27, 2003, 11:46 AM
I've read years ago that one of the original loads for the .357mag was a 158gr bullets pushed to 1400+ FPS. If true, it really outshines what's offered by major manufacturers today (the same weight projectile typically at 1250 FPS).

September 27, 2003, 01:40 PM
Max loads for a .357mag, depending on barrel length, will push a 125gr bullet up to about 1700fps and a 158gr to about 1500fps.

September 27, 2003, 02:21 PM
Yup, AFAIK the .357 mag loads of yore were a 158 grain bullet at 1450 FPS.
Good medicine for deer.
Now .357 hunting loads are 158 at 1200, and range from merely marginal to way too weak for good size deer, depending on bullet design.
10mm is now the minimum I would use for deer.
But the new weak 10mm loads (Like silvertips.) suffer from the same problems, MCNETT's double tap ammo is 10mm deer hunting nirvana.

September 27, 2003, 02:38 PM
"Are there actually "light" magnum loads... and is that by bullet weight or powder load?"

Yes there are light magnum loads. As was mentioned, most factory ammo made today is far lighter than what was manufacturered years ago when the .357 Magnum was first conceived. And these full power .357 loads are easily duplicated by handloads. By the same token, light loads are easily concocted by the handloader. I shoot 99% handloads in my .357s and most of them are not "full power" loads. If I am out punching paper or shooting beer cans there is no reason to shoot full bore loads. Most of my handloads are hotter than .38 Special +P loads, but are far from max. 357 loads. In my K-Framed guns I never fire max. loads from them. I do however have a number of .357s that will handle anything you want to feed them; Ruger Redhawk, Ruger Blackhawk and to a lessor extent the Ruger GP100. I won't hesitate to shoot some hot .357 loads out of my S&W Model 27 or 28 but I don't do this on a regular basis simply because I consider them more of a collector piece and don't want to place undue stress on them. They certainly can take it, but I don't have a good reason to do so. Then of course you get into the idea of shooting .38 Special loads out of your .357 revolver to minimize the stress and strain on the gun. This isn't a .357 load at all, but serves the same purpose as a "light" magnum load while using the same gun. I personally don't shoot .38s out of my .357s very often because I have too much fun shooting them out of my .38s.
A light load would be considered as such because of the powder used and/or the powder charge. You can load any weight bullet light and in fact most any .357 bullet is loaded "light" in the .38 Special.

September 27, 2003, 03:47 PM
When it starts to HURT you are getting close :D

September 27, 2003, 05:27 PM
. . . And please remember that S&W's N Frame – actually its direct predecessors such as the Smith 1917 (.45 ACP) – long-proceeded (many decades) the L frame (581, 586, 681, and 686). It is my understanding that the L frame was developed due to metallic fatigue and cracking problems in K frames (e. g., top-strap) when subjected to extensive, robust .357 magnum loads.

September 27, 2003, 05:46 PM
IIRC, the problem with the K frame, particularly the M-19, came about when the light weight, high velocity loading was in vogue. The smaller bullets, particularly the 125gr, wore the forcing cone and also lead to some stretching of the front strap. TTBOMK, there has never been an issue with the heavier bullets.

The M-19, though, was a compromise. Many duty officers found the larger N frame guns, the 357 and later the M-27 and M-28s too heavy for constant wear. S&W was asked to design a gun that would shoot 357Magnum loads as duty use, 38 Special for pratice, that would be lighter and point as well or better than the N frames. The result was the M-19.

I would hate to guess how many rounds of 357Mag have gone throuogh my M-19s. It's been a bunch though. I tend to select the heavier bullets though with 158 being a favorite. So far, they have held up and despite the popular wisdom, decades and decades later they are still going strong. The M-19, in addition to being a (IMHO) beautiful gun, is also extremely well balanced. I love my N frames but the M-19 is perhaps even more fun to shoot.

Old Fuff
September 27, 2003, 06:41 PM
The original .357 Magnum cartridge was the result of a colaberation between Smith & Wesson, Winchester/Olin ammunition and Phil Sharpe who did a lot of the experimental work and designed the lead 158 grain bullet. Sharpe went up as high as 40,000 PSI at a time when hot .30-06 loads didn't exceed 51,000.

The 40,000 PSI load was listed as "dangerous" because it was way over ratings, but the S&W Magnum revolver showed no ill effects. Most factory loads were around 33,000 PSI which was S&W's stated limit.

When the much lighter model 19 Combat Magnum came on the market it was expected to pass proof testing, and it did. But as has been noted by others here, certain loads with jacketed bullets caused problems.

This caused a move in two directions. Most mainline cartridge manufacturers lightened their .357 Magnum loads while S&W developed and introduced their in-the-middle "L" frame while Ruger discontinued their Security Six/Speed Six line of lighter revolvers and replaced them with the GP-100 and 5-shot SP-101. These revolvers weren't compromises - they could handle both new and older loadings. The Ruger's in particular were built like a brick outhouse. All of this was good, but the ammo people were commited to the lighter loads. Some small speciality companies still load the "hot stuff" and of course handloaders can do the same. But if that's your intent be sure to get a REAL revolver. Don't send a boy too do a man's work.

Old Pete
September 27, 2003, 08:06 PM
We also need to avoid comparing apples and oranges. The published muzzle velocities of the .357 (and other revolver cartridges) before the late 70's were obtained in long pressure barrels without a barrel-cylinder gap. About 1977 or so, SAAMI specified a new pressure-test-barrel configuration with a simulated barrel-cylinder gap and a total length that simulates a 4-inch revolver. The factory muzzle velocities published in the last 25 years are close to what one actually gets from a typical 4-inch revolver.

I do agree that the factory .357 loads have been toned down quite a bit, but not quite as much as the published numbers would indicate.


September 27, 2003, 08:51 PM
I may be wrong, but I seem to remember reading an article written by Paco Kelley who bought some vinatage .357 ammo at a gun show. Using his chronograph he proved to himself that the old ammo was still everything it was supposed to be. It easily hit the velocities that had been reported for the next 50-60 years (as a side note it was interesting that the ammo had appearently not deteriorated at all over the years).
According to him, the old loads were every bit as potent and legend had it.

Standing Wolf
September 27, 2003, 08:56 PM
Most of my .357 magnum loads are light .38 special target loads in the slightly longer cases. When I want to shoot full power .357 magnum rounds, I have to load my own: the factory stuff is considerably lighter than full power.

September 27, 2003, 09:17 PM
While the original .357 Mag was advertised as 158gr at 1515 fps in 1935, it was chrono'ed using a 8-3/4 inch barrel.

In Bill Jordan's book, No Second Place Winner, he indicates that velocities for .357 from 4" revovler is around 1250 fps. This was in 1965.

I know that loads have been softened up. A friend of mine loaded some 173gr Keith bullets over Keith's load of 15gr of 2400 in a .357 case and we got an average of 1460 fps out of his 6" M-27. They were SMOKIN'. Another thing I found interesting was that there was practically no leading in the barrel/forcing cone. Keith really did design a damn good bullet, with the big grease groove and huge front drive band, it was clean and accurate.

I'm getting into reloading just to make some of these screamers.

September 27, 2003, 10:41 PM
Standing Wolf, lets hear some details about you hand loads.
The hottest 357 hand loads I ever made were a mistake. Had a momentary lapse of reason and loaded 8gr of Bullseye, had to beat the cases out of the chambers with a dowel rod. :eek:
Sure glad it was a Ruger.

Mike Irwin
September 27, 2003, 10:47 PM

Paco isn't the only one who has done that.

I did it some years ago with some vintage Winchester .357 Mag. ammo.

Out of a 6" barrel I was getting readings pushing 1,600 fps with 158-gr. bullets.

September 27, 2003, 11:55 PM
Aside from reloading to beyond fullhouse load specs...yes there is full house ammo available. The stuff of yesteryear is very rare to find but I guess can be found. To me a full house loads are a 125 gr getting over 1350 FPS from a 2" barrel...and yes, it does sting from a lighter gun.

There are light loads....typically 110 gr bullets and lighter powders that go in an array of heavier bullets....but WHY?

The Magnum was named that for a reason....WASNT IT? Or am I just a power junky? Hell I want a 9mm ++P++ ....and no I dont want a 357 Sig.

Shoot well

September 28, 2003, 12:23 AM
There are "lighter" magnum loads, the reduced velocity 125 grainers from Remington that give-up 200 fps and the 110 grain loads available in Winchester Whie Box.

September 28, 2003, 01:18 AM
The S&W Model 19 was originally mage after years of persistence by the late great Bill Jordan. He kept asking S&W to build a .357 on the K frame. His reasoning was that America's police officers needed a more powerful weapon than the .38 Special that wouldn't weight them down as much as a Model 27 or 28.

Mr Jordan also advocated the use of .38 Special loads for practice and .357 Magnums for duty.

The Model 19 was never intended to be used with a steady diet of heavy loads. I saw many Police Department Model 19s and 66s in the early 1980s that had been nearly pounded to death by continuous use of heavy 158 grain loads. loads. However the metals used today make the possibility of a K-frame (or smaller) revolver capable of handling a steady diet of such a possibility.

I do know that I have fired some of those old yellow box Western and blue & yellow box Peters loads to tell you that you can tell there's something about them different enough to make you notice when you set one off. Maybe it was a difference in the powder they used back then, but the muzzle flash and recoil impulse sure seemed stronger.

Just my tuppence.

Standing Wolf
September 28, 2003, 10:59 PM
Standing Wolf, lets hear some details about you hand loads.

My most accurate .357 magnum loads consist of standard primers, 2.5 to 3.2 grains of Bullseye, and Speer hollow-based wadcutters in .357 magnum cartridge cases. My Pythons stabilize lighter loads better than my Smith & Wessons. Those would be light target loads even in .38 special.

As for heavy loads, I'm afraid the best I can do is refer you to the better reloading manuals: I don't load an awful lot of hot rod .357 magnum rounds, and would be embarrassed if my loads turned out to be too hot for someone else's gun.

September 29, 2003, 12:34 AM
What IS a "full power" .357 magnum load? Any bullet and powder combination that will produce around 40,000 psi pressure.


Robert inOregon
September 29, 2003, 03:34 AM
Any bullet and powder combination that will produce around 40,000 psi pressure.

Its 43,000 CUP. :cool:

September 29, 2003, 03:48 AM
Is a KaBoom when your CUPs runneth over?

September 29, 2003, 05:21 AM
That was a good one Blues.

September 29, 2003, 05:50 AM
What IS a "full power" .357 magnum load?
Any bullet and powder combination that will produce around 40,000 psi pressure.
Its 43,000 CUP.
Ahhh, now this is where it's beginning to get interesting.
So far, the closest appoximation of the original .357 magnum spec is a 158 gr @ 1500 + fps. (Which BTW, I happen to agree with. 1500 fps was considered a "majic number" velocity)

So, with apologies to Carly Simon,,,,,"these are the good old days"

A quick check of Hodgdon's web site yields this little tid-bit:

COL: 1.580"

LIL'GUN 18.0gr 1577 fps @ 25,800 CUP

Granted, that's out of a 10" barrel - - HOWEVER

it's still roughly 40% under most working pressures for the .357mag!

Since Hornady is using LIL'GUN powder in the .17HRFM already, it wouldn't surprise me at all if they brought out a "true" 158 gr .357mag @ 1500fps+ in the near future.

September 29, 2003, 10:43 AM
This is a very interesting subject, and not the first time it has been thoroughly dissected here, on TFL, and so forth. Without question, it is difficult (impossible) to find fully-potent commercial .357 magnum loads. In fact, most top-quality factory rounds provide a 158 grain projectile with about 1200 FPS muzzle velocity, instead of the 1400+ FPS muzzle velocity of earlier decades.

This said, I wonder if today’s best .357 magnum defensive JHPs might not actually be BETTER man-stoppers (and please note, I am saying man, not automobile or man behind automobile). My thought is ~1200 FPS with a 158 grain bullet should be PLENTY for excellent penetration and expansion; however, today’s “wimpy” loads might reduce carry-through concerns and provide faster follow-up shots. In sum, I suspect the best contemporary .357 magnum commercial rounds (HydraShok, CorBon, Silvertip, Georgia Arms, and so forth) remain a VERY effective anti-personnel load.

How do our experts feel about this?

Thanks and best regards.

September 29, 2003, 02:59 PM
A...My 40,000 response was an approximate number.

B...The question was "What IS a "full power" .357 magnum load? "

C...Not related to the question but I agree that there are projectiles now available that make the cartridge very effective as a man stopper using less than full power loads.


September 29, 2003, 05:46 PM
JAR had it almost right. In the mid 70's when we started qualifying with "full power" .357 loads (125g JHP), there was some 'flame cutting' of the top strap on the M19's. Folks feared it would cut all the way through (never heard of it happening). We continued to shoot them, the flame cutting stopped after a certain point. S&W developed the L frame, we saw the light and started to carry handguns developed in the same (20th) century, i.e. semi autos.

With new bullet designs, "full POWer" loads are not needed to get bullet expansion and penitration. Saves wear and tear on the guns and our wrists.

September 29, 2003, 07:17 PM
I have to pick a nit here.
Yes, I believe bullet design has gotten better over the years. Yes, I think you can buy .357 bullets that expand reliably with less velocity than was previously required.
Yes, I think that you have a very effective anti-personel round combining modern bullets loaded at modern velocities in .357 (as effective as a handgun can be).
But, I wouldn't go as far as to say that full power loads are not needed. Not everyone bases all their ammo decisions on it's performance on human targets. There are those who hunt with the .357 for example and want to get every last bit of performance out of the cartridge they can for shots at odd angles, or against large animals, or at the fringes of the cartridges range. There are people who might want to shoot metallic silhouette just for fun with their .357. There are people who plink at long range........................ etc. who want and I dare say, need, everything they can safely get out of the cartridge.

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