5.7 vs. 9mm: Which Should You Add to the Collection?

5.7 vs. 9mm; who do you have? You have the 9mm round in one corner, a favorite for the military, police, and civilians since Georg Luger created it in 1901. Well, everyone was mostly using .45 at that time, but you get my point.

It’s fast, easy to control, and accurate all day long. And it comes in many different shapes and sizes.

In the other corner, we have the FN 5.7. Popularized in 1990 by the Belgium company FN, the 5.7×28 cartridge has seen its fair share of the combat zone. The 5.7 cartridge is in use by over 40 countries worldwide and has built a reputation for itself over the years.

Now we’re going to put them head to head and see which one takes the cake.

Let’s jump into it.

Summary of the 9mm Cartridge

The 9mm has been around for a long time and has won the hearts of many law enforcement and government agencies around the world.

It is currently used by over 70 countries worldwide, and is the standard side-arm round for NATO countries.

The 9mm was designed to deliver a big punch in a small package and allow the end user to hold more rounds which can be shot with better accuracy and quieter when compared to the .45.

The U.S. Military adopted the 9mm round in 1985 to replace the .45, and in 2018, different branches of our military adopted the Sig Sauer M17 and M18, which are chambered in 9mm.

Here’s more info from Flannel Daddy talking about 9mm ammo.

Summary of 5.7×28

The 5.7 cartridge was literally designed to beat the 9mm. And it does, in many aspects.

The 5.7 is ¾ the weight of the 9mm, more aerodynamic, and has about three times the pressure of the 9mm. And pistols chambered in 5.7 usually hold more rounds than pistols chambered in 9mm.

A bunch of shooters are flocking to the 5.7 round (see our favorite 5.7 guns for more info) for its reliability as well. It was heavily designed after the 5.56 round and shares many of its features.

Here’s a video of the legendary Paul Harrell on 5.7.

Being that the 5.7×28 round was developed to replace the 9mm as requested by NATO, you can expect that the differences will be vast. And they are. On paper, the 5.7 crushes the 9mm in almost any playing field.

When you put them head to head in a real-world scenario, it’s a bit different, and things don’t seem as they do on the spec sheet.

Let’s talk about the things we noticed.

Recoil

When you shoot a pistol chambered in 5.7, you may feel like the recoil is similar to that of the .22. And that’s because it is pretty similar. The 5.7×28 round has 30% less recoil than the 9mm round at almost twice the speed of 9mm.

5.7 rounds are incredibly light in comparison with the 9mm. For example, most 9mm rounds have a standard grain weight of 115 to 147 grains, where the lowest grain for 5.7 is 27 grains and maybe lower.

This plays a huge factor in recoil. Of course, a heavier grain cartridge has more energy and impact, but we’ll talk about that in a minute.

5.7×28 gets its hand raised in the battle for lower felt recoil.

Accuracy

With less recoil comes better accuracy. On top of that, the 5.7×28 round borrows its design aerodynamically from the 5.56. So what you get is a round that shoots with a flatter trajectory and is lightweight.

That’s not to say that the 9mm isn’t accurate; the 9 has a long track history of being one of the most accurate pistol calibers on the market. No wonder it has been in service for 100 years and still going strong.

But the 5.7 still takes the cake in terms of accuracy. 

Pressure

The 9mm has a SAAMI standard pressure of 35,000PSI, and while the 5.7 round has not been standardized by SAAMI, it has a pressure rating of 50,000PSI.

That’s a 25,000-pound difference, and 8,000 less than the 5.56 round that the 5.7 is designed after. Remember, this is coming from a round that is lighter than 9mm, which contributes to the trajectory of the round when it leaves the muzzle.

Even at 38,500 PSI, which is the highest pressure available from 9mm, the 5.7 comes out on top.

Reliability

If it was going to replace the 9mm, it would have to be reliable. With the 9mm being one of the most reliable rounds in the ballistic universe, it would be hard to beat out.

Well, the 5.7 is a pretty reliable round. Is it more reliable than the 9mm? Well, that’s hard to say. There are many factors that come into play with whether the round is reliable or not.

Being that the 5.7 round had to beat out the 9mm in every aspect to be considered for replacing it, it has to be more reliable, correct?

Yes. You are correct.

Since the 5.7×28 round features a bottleneck design, which was a marketing point for Sig Sauer when they came out with the .357 Sig, there is better feed reliability with the 5.7 over the 9mm.

With poor ammo, the aggressive feed ramp on 9mm pistols can sometimes snag up a round when the gun is cycling. This can lead to a failure to feed and the pistol not going into battery (round not fully seated in the chamber).

On the FN Five-SeveN, the chamber has a funnel-like feed ramp that eases the round into the chamber. This results in fewer failures to feed, which helps 5.7×28 take the cake.

Let’s address the elephant in the room. While the 5.7 is better than the 9mm on paper, is it better in real-life situations?

Remember, paper beats rock, but not in this situation.

We’ll discuss this for both soft (urban carry) and hard target (backwoods carry) applications.

Urban Carry

When we say urban carry, we’re talking about having to protect yourself in home defense or out at a Target run with your significant other.

There are a few different things you have to consider when shooting a soft target. You want penetration, but not so much that it hits the person behind your target. A box of ammo should not cost more than what it takes to fill up your F-150. Unless you’re balling like that.

Incapacitation matters more than sending your target to the great beyond, depending on the situation. While knowing where to hit is more important than what you hit it with, we’ll be talking about an average person. None of us were born with aim-bot built in, unfortunately.

That would be cool, though. Just saying.

The 9mm hits a bit harder than 5.7. With the 9mm, you get about 350 ft-lbs of energy when it hits the target. With the 5.7, you get somewhere about 290 ft-lbs of energy. While the 5.7 may travel faster, the 9mm hits harder. 

So in terms of power, the 9mm takes the top spot.

Unless your target is wearing body armor, which they probably aren’t unless you’re John Wick, you may not need armor-piercing capabilities. Not that it’s legal, anyway.

Since the 5.7 had to pierce through armor for NATO, it had to penetrate more than the 9mm, right?

No, actually, it did not. The 5.7 tends to tumble in the target much like the 5.56, which causes more damage inside of the body. But the 9mm gets deeper, and that matters more than they say it does.  

In terms of penetration, the 9mm takes the top spot. 

Here’s a video from Kentucky Ballistics with 9mm and 5.7×28 in ballistics gel.

Now, it is hard to say that the 5.7×28 can be easily beaten by the 9mm since the less felt recoil on the 5.7 allows you to keep your sights on target and put more shots in him if need be. After all, that is why the 9mm is chosen over .45 by many shooters.

The 5.7×28 takes the crown for less felt recoil. 

While many factors go into choosing the best self-defense round, it all boils down to you and what you think is best for you.

But, due to the harder hitting and better penetration of the 9mm in conjunction with the lower cost per round, we give the 9mm the crown in concealed carry and home defense.

Backwoods Carry

While the 9mm packs more of a punch on a soft target, it’s not the recommended round for an 800-pound grizzly. I would not want to get caught out there with anything less than 10mm.

If you have to shoot something small from a distance, 5.7 is the way to go. Since the trajectory is flatter, the bullet is quicker, and it could put small to medium game down with the right shot placement.

But it’s better to have more than less, so for all intents and purposes, I would not recommend either of these rounds for a backwoods carry situation.

Get a 10mm or something bigger. When a sow is trying to protect her cubs, and you’re too close, you don’t want to tickle her.

Unless you’re in big game country, I would recommend the 5.7×28 for its longer effective range than the 9mm.

If you’re in big game country, the 9mm hit’s harder, but it is still not adequate enough unless you train where to hit big game. So just save yourself the trouble and get something bigger.

While the 5.7×28 cartridge may look better on paper than the 9mm, it falls short compared to real-world applications. If you are in the market for a full-size pistol and want to try something new, why not give the FN Five-SeveN a shot and see how you like it? Check out our FN Five-seveN review here.

Do note that 5.7 is more expensive. And for that reason, I’m out. I’ll take a 9mm until I can afford 80 cents a round.

What do you think? Is the 5.7×28 that much better than the 9mm like NATO intended? Let me know what you think below.

Happy shooting!