(Photo Provided by Author.)
February 03, 2025
By LAYNE SIMPSON
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When Smith & Wesson introduced the .357 Magnum in 1935, it was the company’s response to the .38 Super Automatic developed by Colt six years earlier for the Model 1911 pistol. The .38 Super was loaded with a 147-grain FMJ bullet at a velocity of 1,225 fps. At the time, tests performed by Colt had revealed that a bullet from the .38 Super had to be launched at a velocity of 1,200 fps in order to reliably punch through the body of an automobile and still have enough power remaining to put the brakes on its occupant.
If the steel in one of the automobiles driven by gangsters and hoodlums in those days was melted down, it could probably be used to make an entire fleet of today’s Mini Coopers. And while the .38 Super proved capable of doing just that, the .357 Magnum loaded with a slightly heavier bullet at higher velocity may have proved to be even more of a good thing. Two of the first S&W revolvers built in .357 Magnum were presented to FBI Director J. Edgar Hoover and Philip Sharpe, who was instrumental in the development of the cartridge.
Ammunition initially loaded by Winchester had a 158-grain lead SWC bullet. The bullet of a so-called metal-piercing load added a bit later was also lead, but a pointed steel cap on its nose increased penetration. Developed specifically for use by law enforcement officers while on road-block duty, it was commonly called the highway patrol load. There was a time when it was commonly believed that a bullet fired from the .357 Magnum into the engine of an automobile would bring it to a screeching halt.
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As is typical for rifle, pistol, and revolver cases made by Starline, those in .357 Magnum are tops in strength, uniformity, longevity, and overall quality. (Photo Provided by Author.) To see if such was fact or hot air, a high school friend and I pitted my Ruger Blackhawk and factory ammo loaded with various bullets (including the metal-piercing round) against the engine of a Nash Rambler automobile that sat abandoned on his father’s farm. Much to our disappointment, not a single bullet managed to punch through the water jacket of the Nash engine. Splashes of lead on rusty steel were the only evidence that we had been there.
Smith & Wesson also promoted the .357 Magnum for hunting deer and other big game. Major Douglas Wesson, who was a grandson of company co-founder Daniel B. Wesson, used an S&W .357 Magnum revolver with an 8.75-inch barrel on highly publicized hunts in Wyoming and Canada for moose, elk, grizzlies, and pronghorn antelopes. It was written that two shots were required to bag the antelope at 200 yards, but the others were one-shot kills. Winchester and Remington loaded the 158-grain bullet to just over 1,500 fps for more than 800 ft-lbs of energy, not too far behind some of today’s .44 Magnum ammunition. The velocity of the .357 Magnum was later reduced to the present 1,250 fps for 550 ft-lbs of energy.
That Ruger Blackhawk I had during the 1960s accounted for several deer, with all but one standing inside 100 yards. An S&W Model 29 in .44 Magnum eventually became my primary venison harvester, but I continued to use the .357 Magnum when chasing feral hogs with hounds. A 146-grain bullet made by Speer in those days worked fine on deer, and it proved to be enough for up-close shots on pigs ranging in size from small to medium. But when the distance was increased to 50 yards or so and the target was a huge boar with a thick gristle plate covering its vitals, a 170-grain SWC cast of scrap wheelweight metal with a Lyman No. 358429 mold and seated atop 13.0 grains of 2400 powder did a much better job of dropping the bacon.
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The Exercise For this report, I decided to see how the performance of the .357 Magnum cartridge loaded with a slow-burning powder compares when fired from firearms with barrels of various lengths. When it comes to reaching maximum velocities with all available bullet weights, I have found W296 impossible to beat. And since I wanted weight alone to determine velocity differences, I used bullets from the same maker in order to eliminate major differences in bullet shape and diameter.
Hornady XTP bullets weighing 110, 125, 140, 158, and 180 grains fit the bill perfectly. Measured with a Starrett micrometer, diameters were 0.3572 inch for the 110- and 125-grain bullets and 0.3568 inch for the other three. I doubt if a mere 0.0004 inch difference in diameter had enough influence on my test results to matter. The five bullets have the same cannelure-to-nose measurement, and they differ only in full-diameter shank length. When loaded to the same overall cartridge length, free travel prior to rifling engagement is the same for those bullets. The XTP design has long been renowned for accuracy and performance on game. Starline .357 Magnum cases and Federal No. 200 Small Pistol Magnum primers rounded out my selection of top-quality components.
The five upside-down Hornady 0.357-inch XTP bullets at right show that their dimensions from cannelures to noses are the same, while differences in their overall lengths are due to different lengths of their full-diameter shanks. (left to right) Hornady 110-grain XTP, Hornady 125-grain XTP, Hornady 140-grain XTP, Hornady 158-grain XTP, Hornady 180-grain XTP. ( Photo Provided by Author.) All powder charges were thrown with a Redding Competition 10X Pistol/Small Rifle measure . A Redding Supreme .38 Special/.357 Magnum die set was used. After a trip through the carbide sizing die, the mouths of virgin cases were expanded just enough for smooth bulletseating. Recommended overall cartridge length for the five Hornady bullets is the same at 1.590 inches.
The revolver used for .357 Magnum velocity checks was a Dan Wesson Arms Model 715-VH purchased in 1993. Due to its weight (49.5 ounces with 8.0-inch barrel) along with a large hand-filling grip, it is the most comfortable revolver of its caliber I have shot. As a bonus, its single-action trigger pull is both smooth and light. The big revolver was also chambered for a number of other cartridges, including the .357 SuperMag, .375 SuperMag, and .445 SuperMag, all designed by Elgin Gates for handgun metallic silhouette competition where Dan Wesson revolvers had a big following. Mine departed the factory as a Pistol Pac, consisting of a revolver with interchangeable barrels measuring 2.5, 4.0, 6.0, and 8.0 inches. Also included in the hard case was a small hand tool used for switching barrels, a feeler gauge for setting cylinder gap after a barrel switch, front sights with inserts of various colors, and two grips of different sizes and shapes. (See Joel Hutchcroft’s “Hipshots” column in the June 2023 issue for more about Dan Wesson.)
A Dan Wesson Arms Model 715-VH revolver with interchangeable 2.5-inch, 4.0-inch, 6.0-inch, and 8.0-inch barrels was used to test the velocities of full-power charges of W296 behind five Hornady 0.357-inch bullets weighing from 110 to 180 grains. ( Photo Provided by Author.) A Ruger-made Marlin 1894 lever-action rifle with a barrel measuring 18.125 inches from boltface to muzzle was also used for checking velocities. Adding a Bushnell 1.5-4.5X Scopechief IV made it ideal for checking accuracy at 50 yards as well. Also serving as a paper-puncher at that distance was an old, reliable 6.0-inch-barreled Smith & Wesson Model 686 revolver wearing an equally reliable Bausch & Lomb Elite 3000 scope in 2-6X magnification. The carbine rested on sandbags, while the revolver was shot from an MTM K-Zone pistol rest with the butt resting firmly on a thin sandbag.
The Results So what did I learn? Well, regardless of barrel length or bullet weight, velocity variation of slow-burning W296 ranged from a low of 11 fps to a high of 24 fps, which I consider to be quite good. Then we have velocity gain per inch of barrel increase. Increasing barrel length from 4.0 to 6.0 inches resulted in an average gain of 120 fps (60 fps per inch). Going from a barrel length of 6.0 inches to 8.0 inches increased average velocity by 119 fps, for virtually the same gain per inch. Increasing barrel length from 8.0 inches to 18.125 inches resulted in an average gain of 469 fps, or roughly 47 fps per inch of barrel length increase. As barrel length is increased beyond 16 inches or so, velocity gain per each additional inch of barrel increase will decrease due to the extremely high expansion ratio of the .357 Magnum cartridge. Think of it as a .22 Long Rifle on steroids.
As bullet weight increases, velocity gain in longer barrels decreases, and that came as no surprise. When going from a 2.5-inch barrel to an 8.0-inch barrel, respective velocity increases for the 110-grain, 125-grain, 140-grain, 158-grain, and 180-grain bullets were 506 fps, 396 fps, 362 fps, 251 fps, and 210 fps. When switching from a 2.5-inch barrel to a barrel measuring 18.125 inches, the 110-grain bullet gained more than twice as much velocity as the 180-grain bullet (1,114 fps versus 519 fps). Powder charge weights used with all bullet weights were considered maximum or close to it by reliable sources.
A Ruger-made Marlin 1894 and a Smith & Wesson Model 686 were used for testing the accuracy of the .357 Magnum loads at 50 yards. ( Photo Provided by Author.) As expected, a blossom of bright muzzle flash was produced when W296 burned in the 2.5-inch and 4.0-inch barrels , and since I was shooting during the day when ambient light was good, I did not consider it to be a negative. Switching to the 6.0-inch and 8.0-inch barrels of the Dan Wesson revolver reduced flash to barely noticeable. During the few times I have shot feral pigs with that revolver, it was wearing one of its two longest barrels.
I also proved to my own satisfaction that from a practical point of view, there is not a lot of difference in accuracy among the five Hornady bullets fired from my guns. Among several factors that could be at work here, all bullets being quite close to the same diameter along with all traveling the same distance prior to engaging the rifling had to be influential. Something I was already aware of is the ability of W296 to reach velocities with bullets weighing from 110 grains to 180 grains that no other single propellant I have tried can match.
(Data Provided by Author.) The grand old .357 Magnum is a survivor, and it certainly deserves to be. At a time when 9mm pistols virtually own the personal-defense market, and cartridges ranging in power from .44 Magnum on up are most often seen in the hunting fields, the .357 Magnum marches on with a variety of excellent ammunition options offered by various companies. Neither is there a scarcity of revolvers from Smith & Wesson, Ruger, Kimber, Colt, Freedom Arms, Taurus, Rossi, Nighthawk Custom, and others that I might be unintentionally overlooking. And then we have lever-action rifles in .357 Magnum offered by several companies, with the Marlin 1894 being made by Ruger quite impressive in accuracy, quality, and aesthetics.
(Data Provided by Author.) The option of shooting softer-recoiling .38 Special ammunition available with a great variety of load options in .357 Magnum revolvers is one reason why the 89-year-old youngster has been and continues to be so popular. During most of my life I have owned at least one revolver in .357 Magnum, and I see no reason why that should change.