.357 Magnum vs. 10mm Auto: Old School vs. New School in Magnum Power

by Terril Hebert

June 27, 2023

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For every action, there is an equal and opposite reaction. If man-portable power is what you seek, nothing beats a good long gun. Rifle and shotgun rounds can deliver a larger payload at higher velocities than any conventional handgun round. Handguns, by virtue of being small and manageable, are generally not going to be chambered in those rounds. Even if it is possible, it would not be practical to carry around or shoot.

Handgun rounds are necessarily weaker. They won’t have the same flat trajectory, high velocity, or terminal ballistics as a rifle or shotgun will have. But that doesn’t mean some handgun cartridges can’t be called upon to do bigger jobs. Some handgun rounds are effective against barriers and both two-legged and four-legged predators. Two of the most popular handgun rounds that excel at this are the .357 Magnum and the 10mm Auto.

The .357 Magnum and 10mm cartridges are two cartridges with three lives: one in law enforcement, one in personal protection, and the other as a wilderness tool. Your preference for one of the other might boil down to your preference for a revolver with the .357 or an autoloading pistol with the 10mm. But there are more similarities and differences than you might think. In this overview, we will cover the .357 Magnum and 10mm Auto in both their historical context and their present utility as defensive tools.

357 Magnum vs. 10mm Auto Spec Comparison

357 Magnum Ammo

357 Magnum

Parent Case 38 Special
Bullet Weight (gr) 110-180
Bullet Diameter (in) 0.358
Case Length (in) 1.29
Case Volume (gr) 26.2
Max Pressure (SAAMI) 45,000 psi
10mm Cartridge

10mm Cartridge

Parent Case 30 Remington
Bullet Weight (gr) 155-200
Bullet Diameter (in) 0.400
Case Length (in) 0.99
Case Volume (gr) 24.1
Max Pressure (SAAMI) 37,500 psi

Why Compare the .357 Magnum and 10mm?

357 Mag vs 10mm Auto Side by Side
357 Mag vs 10mm Auto Side by Side

A standard bottle of wine holds approximately 750 milliliters. A larger bottle can vary in size, but it is generally called a magnum. The .357 Magnum was designed to get the most out of existing revolver designs, as was the 10mm Auto for large-framed automatic pistols. Subsequently, larger magnums have emerged and the .357 and 10mm are now viewed as the smallest magnum cartridges.

But both cartridges in their respective platforms have been around the longest and are chambered in handguns that most of us can actually carry day-to-day. Both rounds, in their hardest loadings, are bear-stoppers, yet both are also proven in the street. Thanks to their track record and commercial acceptance, the .357 Magnum and 10mm are the most affordable and accessible magnum rounds to hook into, whether the task is personal protection or wilderness work.

The .357 Magnum: The Original

It isn’t every day we can say that we invented a handgun round to defeat an automobile. But that was part of the impetus for the development of the .357 Magnum cartridge by Smith & Wesson in 1935. After the 1921 Depression, automobile sales surged and Prohibition criminality surged. Inner-city rum runners trafficked booze and ran extortion rings. Motor bandits traveled the country, making the spirits and holding over banks, often using more force than finesse in their escapes from law enforcement.

357 vs 10mm HP 357

Ford and Chevrolet jockeyed to make first the V6 and the V8 engine and the bandits paid the premium in order to outrun the cops. The FBI and their state and local law enforcement allies responded with more powerful cars of their own. This motorized environment ensured that the cops would have to take shots around or through automobiles to hit their targets. Unfortunately, the .38 Special revolvers that most agents carried could not penetrate the solid steel frames of a typical car.

There are several men often credited with the development of the round. Elmer Keith, a well-known writer and lawman, uncovered that the .38 Special’s case capacity was not being used to its fullest potential. He began developing warmer loads to shoot through Smith & Wesson’s large .44 caliber framed wheel gun. Concurrently, Doug B. Wesson of Smith & Wesson, in conjunction with Phil Sharpe, a technical advisor for the NRA, developed the .357 Magnum. It uses a jacketed bullet of the same diameter as the .38 Special. The case is virtually identical, except it is lengthened by 1/8 of an inch so that they could not fire the new cartridge in guns made for standard .38 Special cartridges.

Mr. Wesson was anxious to reassert his company’s name in law enforcement circles and traveled the country to demonstrate the new cartridge and the Smith & Wesson .357 Magnum revolver. The new round was demonstrated to shoot through engine blocks and ballistic vests. Wesson took the gun to Alaska where he floored walruses and grizzly bear.

The .357 Magnum was a hot seller even in the depths of the Depression. Revolvers chambered for the round continued to serve concurrently with existing .38 Special revolvers until law enforcement shied away from revolvers beginning in the mid-1980s. It is during this transition from wheel gun to autoloader where the story of the 10mm picks up steam.

Find out what our favorite 357 Magnum revolvers are!

.357 Magnum Pros and Cons

  • High Ballistic Coefficient – With loadings of identical weight, the smaller diameter .357 Magnum will have a longer bullet, or higher ballistic coefficient, than the .40 caliber bullet of the 10mm. This yields better long range wind and drop resistance and better penetration.
  • Availability – The .357 Magnum is the most available magnum cartridge out there. Load variety is also plentiful.
  • Power Potential – With its larger case capacity, the .357 Magnum can be loaded hotter than the 10mm, although it usually is not.
  • Rounds Limited – Most .357 Magnum handguns are revolvers with capacities of 5-8 rounds.
  • Light-Grained – Most available ammunition range between 125-158 grain.

Great .357 Magnum Ammo

Here are some of our favorite ammo deals for .357 Magnum.

Hunting Ammo

Federal 158 grain JSP

Federal 158 grain JSP

  • Original 1930s load
  • Inexpensive
  • Flat lead soft-point for uniform penetration and expansion in game
Marketplace
Cost Per Round
Gun.deals $0.57
Brownells $0.63
Target Sports USA $0.65

Defensive Ammo

Remington HTP 357 Magnum125 grain JHP

Remington HTP 125 grain JHP

  • A popular law enforcement option
  • Over 1400 feet per second out of a four-inch barreled revolver
  • Standard of measure for other defensive handgun cartridges
Marketplace
Cost Per Round
Gun.deals $1.17
Target Sports USA $1.35
Natchez $1.42

The 10mm Auto: Magnum Power in a New Pistol

In the 1980s, the revolver was still the fight-stopping tool of choice, but auto pistols had been around for decades and had fans of their own. Then, as now, the auto pistol had its advantages. The Colt 1911 of the day had an eight-round capacity and could be reloaded quickly with detachable magazines. A typical revolver ran dry after six rounds, and reloading with loose rounds or speed loaders was easy to jinx.

357 vs 10mm HP 10mm

Col. Jeff Cooper, the founder of the American Pistol Institute, favored the 1911 and its technical advantages over the revolver. On the other hand, semi-auto pistols had their disadvantages, among them was the compromised ammunition they used. Conventional pistol ammunition had to be short in order to fit into magazine that would go into a grip of a pistol—and still allow you to get a grip.

Although rounds like the 45 ACP were no slouch, they were not magnum status. Cooper and his adherents started developing a cartridge around the old .30 Remington case that used a .40 caliber bullet. In 1983, Norma ironed out the kinks of the new 10mm cartridge and it debuted in the Dornaus & Dixon Bren Ten pistol. The round featured a 200-grain bullet traveling at about 1200 feet per second—somewhat slower than the .357, but with more weight behind it. The pistol itself was a failure, but the round got the attention of the FBI as it hunted for a new platform to replace its revolvers.

At the time, most FBI agents were authorized to carry .357 Magnum revolvers loaded with .38 Special +P ammunition. Those agents who were SWAT trained could opt to carry a 9mm semi-automatic pistol. They found a scapegoat for the 1986 FBI Miami Dade shootout in the weaponry the agents were armed with. Some agents were hit while reloading their revolvers, while the 9mm semi-autos were deemed ballistically unsatisfactory.

The 10mm Auto showed promise. It was chambered in a higher capacity auto pistol to solve the revolver issue and it had more power than the .38 Special +P and 9mm Luger cartridges. In 1990, the FBI adopted the 10mm in the form of the Smith & Wesson 1006 double-action pistol. But they soon realized that the cartridge was too much gun for most agents. The FBI collaborated with Smith & Wesson and Federal Premium to create a 10mm Lite load. Smith eventually figured out that the case could be shortened further and the new .40 caliber round could be easily configured to work in existing 9mm pistols. The 40 S&W was born, and it was adopted instead. The 10mm still had its adherents and in recent years, cartridge availability and pistols chambered for the round have grown exponentially.

Here is a list of our top 10mm handguns. We also have what might be our new favorite 10mm handgun review.

Glock 20 Glock 20 Gen 5 MOS

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Glock 20 Gen 5 Review

Glock 20 Gen 5 MOS

The latest update of the pistol that’s been revolutionizing the world since the late ’80s and bringing the 10mm into mainstream

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  • Reliability A+
  • Ergonomics A
  • Accuracy A
  • Value A

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10mm Auto Pros and Cons

  • More Mass – The 10mm Auto, on the whole, will be loaded with a heavier-grained and wider .40 caliber projectile. Those who favor bullets with mass will be more satisfied with the 10mm.
  • Short and Rimless – Although its 25mm case length is long for a pistol cartridge, the 10mm is shorter than ordinary magnum rounds and it is rimless, allowing for smooth feeding in an autoloading pistol.
  • Auto Loading – Attempts at a .357 Magnum autoloader are not nearly as reliable.
  • Underloading – The 10mm Lite round was a phase of development that should have died with the .40 S&W round. Many factory offerings for the 10mm are, in fact, loaded to .40 S&W specifications and not to their full potential.
  • Availability – Despite its resurgence, 10mm handguns and ammunition are not as available as the .357 Magnum.

Great 10mm Ammo

Here are some deals on our favorite 10mm ammo.

Hunting Ammo

Federal Fusion 200 grain Bonded Soft Point

Federal Fusion 200 grain Bonded Soft Point

  • bonded soft-point bullet for maximum weight retention and controlled expansion
  • loaded to 1200 feet per second
Marketplace
Cost Per Round
Gun.deals $1.35
Brownells $1.45
Palmetto State Armory $1.60

Defensive Ammo

Hornady Custom 155 grain JHP

Hornady Custom 155 grain JHP

  • light XTP hollow-point for clothing-blind performance on target
  • penetrates upwards of nineteen-inches in 10% ordinance gelatin
Marketplace
Cost Per Round
Gun.deals $1.05
Sportsmans Guide $1.09
Optics Planet $1.22

.357 Magnum vs 10mm Ballistic Comparison

The 10mm Auto, as Norma originally loaded it, is continually touted as a semi-auto equivalent to the .41 Magnum revolver cartridge. Both are .40 caliber rounds using 200 grain bullets, traveling at about 1200 feet per second. The comparison is somewhat misplaced, however. The .41 Magnum, when it was introduced in 1964, suffered much of the same fate as the 10mm years later. They envisioned the .41 as a 210 grain bullet traveling at 1400 feet per second, but they downloaded it for commercial use. When loaded to their full potential, the 10mm’s velocity and energy territory overlap more with the .357 than it does the .41.

By the numbers, the 10mm Auto can chuck a 200-grain bullet at about 1200 feet per second out of a typical five-inch barreled autoloader. A four-inch barreled revolver can expect to yield upwards of 1500 feet per second using a 125-grain bullet. In terms of energy foot pounds, the 10mm yields 639 foot pounds of energy. The .357 gives us 625. That is not enough difference to talk about, but what is worth noting is how that energy is transferred. The lighter-grained .357 with its higher velocity will have excellent terminal performance but may not go very far through dense bone and the thick muscle of larger animals like the heavier 10 will. But ordinary 10mm loads loaded to their potential might be too much for thinner targets.

In my own testing using a 4-inch Smith & Wesson Model 27 and a 3 ¾ inch Glock 29, I shot a few different hollow-point and non-expanding projectiles and found that the .357’s penetrating ability goes up with grain size as expansion goes down, while the 10mm penetrates less with lighter projectiles. Buffalo Bore loads the .357 and 10mm Auto to their maximum potential in their Outdoorsman line of hard-cast semi-wadcutter loadings. In the Model 27, I could post the .357 Magnum 180 grain load at an honest 1400 feet per second over my chronograph. The Glock 29 has a slightly shorter barrel, but the 220 grain 10mm load’s velocity clocked in at only 1100 feet per second. The energy foot pounds between them were close, but the .357 Magnum had more energy foot pounds and its higher ballistic coefficient gave it a few more inches of penetrating power through ballistic gel and 2×4 barriers.

Glock 29 and SW 357
Glock 29 vs Smith and Wesson in 357

When maxed out, the .357 Magnum is marginally more powerful, but both the .357 and the 10mm cartridges themselves are not the full story. Gear selection matters to get the most out of each round and each will have their own advantages. The 10mm Auto is now chambered in a few revolvers but its primary advantage is in an autoloader platform. My Glock 29 is a subcompact 10mm that holds ten rounds of ammunition. That Model 27 .357 holds six rounds. A conventional 10mm pistol like the Glock 20 will hold fifteen rounds, while the newest .357s can hold eight in their cylinder. Although a quality revolver is less prone to user-induced malfunctions, both platforms have their issues. A 10mm Auto depends on the power level and bullet profile of the round in question to cycle reliably. Primers in some .357 Magnum loads can back out against the recoil shield of a revolver, freezing the cylinder up on firing.

10mm revolvers like the Smith & Wesson 610 and Ruger Match Champion exist but rely on fragile moon clips to eject the rimless ammunition. Likewise, .357 Magnum autoloaders exist, but I have yet to meet one that works correctly.

Barrel length and pistol size also comes into play. The revolver has the advantage of having a greater effective barrel length. A round coming from a .357 Magnum revolver with a 4-inch barrel will have 4 inches of barrel travel. A hypothetical 4-inch 10mm pistol will have less barrel travel as we count the chamber in barrel length. We can also have the revolver in smaller, lightweight packages like a snub nose J-frame like the Smith & Wesson Model 360 or the Ruger LCR. But these guns sacrifice ballistic potential and are obnoxious to shoot, as are the few small 10mm pistols around like my G29. A mid-size or large frame revolver or autoloader in either caliber is not obnoxious to shoot, although recoil and blast will be greater than typical pistol calibers.

Our Take 

S&W 686 Plus
S&W 686 Plus

The .357 Magnum and 10mm Auto are two of the most useful handgun cartridges out there. Both are proven against lethal two-legged threats as well as the largest North American big game. But that extra power comes at a price. Over more conventional options, .357 and 10mm handguns and ammunition are more expensive and a bit less available. Recoil and blast from both rounds is not onerous, but both are certainly not great for the new shooter. Indeed, some loadings can be too powerful, even for the pistol in question. But if you are willing to work with either round, they will serve you well and much of the particulars of the caliber and load of your choice is going to be dictated by your preference for the revolver over the autoloader.

All I will say to that is to go for what you know. I have more trigger time with revolvers, know their limitations, and like the slight edge the .357 Magnum can have over the 10mm. I also like the ability to use lower-recoil .38 Special ammunition if I so choose. But if you already own an autoloader, a quality 10mm 1911, Glock, or Sig is right up your ally and just as capable of the bigger tasks. But if you ever get the chance, check out both.

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About Terril Hebert

Terril is an economic historian with a penchant for all things firearm related. Originally a pot hunter hailing from south Louisiana, he currently covers firearms and reloading topics in print and on his All Outdoors YouTube page. When he isn't delving into rimfire ballistics, pocket pistols, and colonial arms, Terril can be found perfecting his fire-starting techniques, photographing wildlife, getting lost in the archives, or working on a novel.

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