5.7×28 vs 9mm

During the spring of 2022, an armed man attacked shoppers at a Buffalo grocery store. The store’s security guard, a retired police lieutenant, fired at and hit the attacker.

The shots did not penetrate the assailant’s body armor.

The attacker killed the guard and was able to continue his horrific crime. By the end, ten people were killed.

In New Orleans, on New Year’s Day 2025, a radicalized U.S. citizen, motivated by ISIS and other terrorist organizations, killed 14 people and wounded dozens more. He too was wearing body armor.

The chances of a person being attacked by an armed assailant, let alone one wearing a bulletproof vest, is probably small. But, as these news reports show, it can happen.

These reports, and others, have caused many people to reconsider their 9mm self-defense handguns. Perhaps they need something that can provide reliable protection even if the assailant is wearing armor. This thinking has led many to the FN 5.7x28mm, commonly known as the “five-seven.”

This fast, light round was designed specifically for distance, accuracy, and terminal ballistics. In addition, it was intended to penetrate body armor.

But can this round defeat the 9mm in speed, energy, accuracy, and terminal ballistics? Should we leave our “nines” in the gun safe and face the world with a 5.7x28mm?

9mm Luger vs FN 5.7x28mm: Physical Specs

Size and Shape

Physically, these are two very different rounds. The 5.7, frankly, looks more like a bottlenecked rifle round than a handgun cartridge. Specifically, it has a large case relative to its bullet, which is usually a recipe for speed. The 9mm Luger, on the other hand, has a straight-wall profile.

There is also a clear difference in bullet weight, as the 9mm Luger packs rounds between 70 and 150 grains, while the 5.7 only goes to 62 grains.

Market: Availability and Pricing

The 9mm Luger is the most popular handgun cartridge in the country. It has mass market adoption from both consumers and manufacturers, which means users can find 9×19 ammo for virtually any purpose. In addition, they are usually more affordable.

But 5.7x28mm ammo does have support, especially (but not exclusively) from European brands. Makers like Fiocchi, Prvi Partizan, Federal, Speer, and FN Ammunition give users plenty of options, including target and self-defense rounds.

You can find ammo for both cartridges, but the 9mm is much cheaper. For example, when this article was written a 500-round box of 115-grain 9mm American Eagle FMJ ammo from Federal was $0.28 per shot, while the same product in 40-grain 5.7 ammo was $0.68 per shot. That $0.40 per bang can add up quickly.

Firearm Capacity

Another difference between these rounds, one that rarely gets discussed, is firearm capacity. There are lots of firearms for the 9mm Luger, and many carry over 15 rounds in the magazine; the max (without an extended magazine) is around 20. The 5.7, however, goes even higher, with some touting as many as 22 rounds. This gives users two more shots, which could make a difference in a life-or-death situation.

9mm Luger vs 5.7x28mm: A Performance Analysis

Conducting a fair ballistics comparison between these two is tough, largely because the 5.7 comes in a limited variety and few manufacturers provide consistent data. However, we were able to look at two products from each cartridge and create a nearly apples-to-apples comparison…

9mm vs 5.7×28 Velocity

	Muzzle (fps)	25 yards	50 yards
9mm Luger, 124 grain Speer Gold Dot	1,150	1,092	1,044
5.7x28, 40 grain Speer Gold Dot	1,800	1,651	1,510
9mm, 124 grain Federal American Eagle	1,150	1,095	1,049
5.7x28, 40 grain Federal American Eagle	1,655	1,514	1,387

Higher speed was one of the major goals for the 5.7. It seems to have achieved this mark, as it holds velocity stats that surpass most handgun rounds. With its moderate case and light bullet, this round has speeds reaching 1,800 fps, while the 9mm usually sits around 1,000 to 1,200 fps.

Energy Compared