5.7 vs. 9mm: Has the 9mm Finally Been Replaced?

When you first start comparing the 9mm and 5.7x28mm, you might think they’re radically different. The 9mm looks like a traditional semi-automatic handgun cartridge, and its bullets are significantly heavier.

Conversely, the 5.7mm resembles a miniature semi-auto rifle cartridge. Its bullets are much lighter, and also appear to be more aerodynamic.

Are the two rounds really as different as they seem to be – and if they are, does the newer 5.7 succeed at outperforming the 9mm? Or are the 9mm loyalists (such as myself) correct when they say there’s no real advantage to switching over? Let’s thoroughly compare the rounds and determine the winner of the 5.7 vs. 9mm debate once and for all!

5.7mm vs. 9mm: Differences and Similarities

FN Herstal developed the 5.7 to replace the 9mm: a challenging task. If FN Herstal succeeded, then we should expect the 5.7 to outperform the 9mm in nearly every measurable aspect.

Don’t count on the 9mm to go down without a fight, though. There are good reasons why it’s stayed so popular for over 120 years. Convincing its many fans to switch will prove challenging no matter the conclusion of this article.

Cartridge Specs

The 5.7x28mm cartridge is narrower but longer than the 9x19mm Parabellum.

Most 9mm bullets weigh 115, 124, or 147 grains; substantially heavier than the 5.7’s usual 27 and 40 grain bullets.

The 5.7’s narrower, lighter bullets permit the design of higher-capacity magazines, thus enabling the shooter to carry more rounds.

If you’re looking for a small yet powerful round – like many law enforcement and government agencies currently are – then the 5.7 easily wins this matchup.

Recoil

Neither cartridge is known for having heavy recoil. Fans of the 9mm often argue that this is one significant advantage in the 9mm vs. 44 ACP debate, as follow-up shots tend to be more accurate when there is less recoil.

However, the 9mm has been outdone in terms of recoil. Although it may attain higher muzzle velocities, the 5.7’s lighter bullets and powder charges grant it undeniably lighter felt recoil. I’ve never considered the 9mm to have overbearing recoil, even while firing heavy self-defense loads. Even so, the 5.7 kicks more softly.

Granted, a heavier firearm will produce less recoil, although carrying one around all day can be tiring.

I give the advantage to the 5.7. It generates around one-third less recoil than the 9mm – the latter of which isn’t known for having much recoil in its own right.

Trajectory

Since both rounds are designed for handguns and submachine guns, their trajectories will not be as impressively flat as those belonging to cartridges intended for long-range shooting.

Most shooters prefer a flat trajectory, because it requires fewer calculations and adjustments.

At close range, differences between these rounds’ trajectories are minimal. However, the faster bullets of 5.7 ammo exhibit flatter trajectories than the bulkier 9mm rounds as distance to the target increases.

The 9mm was designed to be lethal out to 50 meters. While it is technically lethal beyond that range, the bullet’s trajectory doesn’t allow it to be effective at long range – even when fired from a carbine.

The 5.7 was developed to effectively pierce body armor at 200 meters. It needs a flat trajectory to be accurate at that distance – the reason why it wins this category.

Accuracy

Accuracy depends on the shooter’s skill level, the gun, the quality of the ammo, recoil, and bullet trajectory.

The more recoil a gun has, the less accurately the average shooter will fire it. This is partly because the shooter will anticipate heavy recoil, thus jerking the trigger instead of steadily squeezing it.

These two rounds’ accuracy will appear very similar over the close ranges they are designed to cover.

However, the 5.7x28mm will begin showing its superior accuracy over longer distances, largely due to its lighter recoil and flatter trajectory.

Stopping Power

“Stopping power” is an overrated and misunderstood metric for cartridges. It is determined by several factors, including capacity for penetration and wound channel diameter: two variables that are essentially mooted by a single well-placed shot.

The more efficiently a bullet penetrates and the larger the wound channel it inflicts, the more stopping power it is considered to have. A higher-velocity round often achieves better penetration, but not always.

The 5.7 has a higher muzzle velocity. Its bullet is also narrower. These two qualities might have helped it penetrate more effectively than the 9mm if not for one fact: The 5.7 bullet is substantially lighter than the 9mm’s, and reaches its target with considerably less momentum as a result. For this reason, the 9mm bullet generally penetrates better than the 5.7. The 9mm finally has a win.

9mm vs. 5.7 for Self-Defense

I don’t expect to settle this discussion in this short section, because I know how long the 9 vs. 40 vs. 45 debate has raged. As the 5.7 continues increasing in popularity, I believe it will also be included in debates to determine the best self-defense cartridge.

The 9mm has proven itself to be an effective personal defense cartridge by law enforcement and civilians alike.

Since the 5.7 was designed to replace the 9mm, it should at the very least be equally effective for self-defense. Militaries and law enforcement agencies certainly believe this to be true, as many are issuing the new ammunition to their personnel.

Despite this, the 9mm remains my choice for concealed carry. That’s partly because I’m already so accustomed to it; partly due to the availability of guns and ammo. More options make it much easier to find the gun and ammo that fit you best.

Home Defense

For a home defense round, I choose a 9mm because of the availability of guns and ammo. This means I’ll consistently find firearms and ammunition to restock my supply. The 9mm wins the personal defense weapon section, but this could change as the popularity of the 5.7 caliber increases and more guns and ammo options begin hitting the market.

Ammo Cost & Availability

The 9mm has existed for over a century. Hundreds of manufacturers currently produce the most popular centerfire handgun ammo on the planet. You can familiarize yourself with a few of them on our 9x19mm ammo page.

One downside to 9mm’s popularity is that it becomes one of the first types of ammo to vanish during a shortage. It’s also one of the first to come back into stock, however. Availability might be delayed, but not for long.

For more ammo options, browse our inventory of Remington 9mm ammo, PMC 9mm ammo and Fiocchi 9mm ammo.

Buying in bulk is always smart. Make sure to check out our stock of 9mm bulk ammo, too!

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Source: https://freedombunker.com/2025/05/26/57-vs-9mm/