When discussing handgun calibers, it is inevitable that the 9mm vs. 357 Magnum debate will arise.
Although the decision between the 9mm Luger and 357 Magnum really boils down to whether you prefer a semi-automatic handgun or a revolver, there are specific benefits to each cartridge that could sway a shooter one direction or the other.
In this article, we will take an in-depth look at the 9mm and 357 Magnum and help you understand which handgun cartridge is better for your needs.
What Is the Difference Between .357 Magnum and 9mm?
The primary difference between 357 Magnum and 9mm is that the 357 Mag is a revolver cartridge and the 9mm Luger is designed for semi-auto pistols. The 357 Magnum is a rimmed cartridge with higher velocity, muzzle energy, and recoil, while the 9mm Luger is a rimless cartridge with lower recoil and a magazine that has higher capacity than a revolver’s cylinder.
Stopping Power/Kinetic Energy
Stopping power is one of those ambiguous terms that gets thrown around campfires and gun store counters despite being completely unquantifiable. You’ll hear stories of how boutique rounds like the 357 SIG have “More stopping power than a 380 Auto,” or how “The 45 ACP is a real man stopper.”
The important thing to remember is that shot placement is more important than any ballistic values. A 22 LR between the eyes will always be more lethal than a 500 Smith & Wesson Magnum to the hand.
However, we can quantify how many ft-lbs of force are imparted upon the target for each cartridge.
Muzzle energy is solely derived from two factors: bullet weight, and muzzle velocity at the instant of impact. Likewise, striking energy at any point downrange is calculated using bullet weight and velocity at the instant of impact.
If there’s one thing the 357 Magnum is known for, it’s power. It got the “magnum” designation for good reason, as the 357 has exceptional muzzle energy for a revolver round.
Looking at the ballistics tables below, we see that the 357 Magnum has higher muzzle energy than most of the handgun rounds listed.
On average, the 357 has about 600 ft-lbs muzzle energy, compared to 340 ft-lbs for 9mm.
But all that energy comes at the cost of recoil.
Recoil
Recoil is an important consideration when purchasing a new self-defense handgun. A round with heavy recoil will be more difficult to control and slow the rate of accurate follow-up shots.
Recoil is partly determined by muzzle velocity (measured in feet per second; fps) and bullet weight. The faster a bullet travels, the harder it pushes back on the shooter. A heavier bullet requires more force to push it through the barrel, which is returned to the shooter’s wrists as recoil.
The 9mm is well known for being soft-shooting and having lower recoil. This makes it extremely popular among military and law enforcement personnel. Civilians are no less fond of its relatively gentle kick, which facilitates rapid follow-up shots.
By comparison, the 357 Magnum is known for having stout recoil, as all that added propellant and bullet mass comes at a price.
On average, the 357 Mag shooter should feel around 10 foot-pounds (ft-lbs) of recoil – over twice as much as the 9mm’s ft-lbs of recoil.
The 9mm Luger is the clear winner in terms of recoil.
Velocity/Penetration
Muzzle velocity is very important when it comes to self-defense rounds, as higher velocity typically correlates to deeper penetration into the target. Penetration is important, as a bullet must reach and effectively damage vital organs in order to quickly incapacitate a threat.
Muzzle velocity is dependent upon several factors that include (but are not limited to) barrel length, bullet weight, and propellant charge.
Barrel length is something that some shooters might not consider when looking at muzzle velocity, but should. A handgun round fired from a 2" barrel will have lower muzzle velocity than if it were fired from a 4" barrel.
Looking at the ballistics tables below, we can see that 357 Magnum loads generally have higher muzzle velocity than comparable 9mm alternatives.
Take, for example, the 357 Mag 125 grain bullet and 9mm 124 grain bullet. They share similar weights, but the 357 has a muzzle velocity of 1,450 fps; the 9mm, 1,150 fps. Even the Federal HST 9mm +P 124 grain load’s hot 1,200 fps muzzle velocity cannot hold a candle to the 357.
It’s clear that the revolver cartridge is superior in terms of velocity. But how about penetration?
The FBI standardized ammo penetration testing in the wake of its famously tragic 1986 Miami shootout. FBI test protocol states that a jacketed hollow point (JHP) bullet should penetrate no less than 12” and no more than 18” into a block of 10% ballistic gelatin (when fired from a distance of 10’).
The terminal performance of 1980s-era 9mm Luger self-defense ammo was not spectacular. However, hollow point bullet design has advanced considerably over the years, bringing the 9mm Parabellum back into favor with the FBI and other law enforcement agencies.
Both the 357 and 9mm are capable of satisfying the FBI’s minimum penetration requirements. However, because the 357 Mag is designed to attain higher muzzle velocity, it generally penetrates deeper than the 9mm Luger.
Deeper penetration can be as much a liability as an asset, and over-penetration is a real issue with 357 Magnum. It is critical to evaluate the self-defense ammo you have chosen for your 357 Magnum revolver. Winchester Defender, Speer Gold Dot, and Remington Golden Saber ammo are all excellent choices that you can pick up here at Ammo.com.
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