4.6x30mm vs 5.7x28mm – Battle of the PDW

4.6x30mm vs 5.7x39mm
June 13, 2022  
Categories: Assorted Ramblings
Tags: PDW

The world of personal defense rounds settles on a total of two cartridges. One being the famed Stargate Command approved 5.7×28 and the other being the’ you suck, and we hate you’ 4.6×30 from HK. The idea of two rounds designed with a similar purpose leads me to ask: which one is better, 4.6x30mm vs 5.7x28mm? It’s not like we have a ton of 4.6x30mm guns to play with compared to 5.7x28mm, but we do have Hornady’s ballistic calculator and a bottle of Basil Hayden’s at hand.

A Little History Behind the 4.6x30mm and the 5.7x28mm

In the 1990s, NATO was looking for a personal defense weapon for not-frontline troops. They wanted truck drivers, mechanics, mailmen, and others to be armed but they thought a rifle was a bit too much. Why not a handgun? Well, in the face of actual combat, handguns suck. Sure they are great for concealed carry, but no one wants to get stuck with a handgun in a rifle fight.

5.7x28mm cartridges

What’s in between? A submachine gun? Sure, but even then, after 100 yards, a 9mm ain’t doing much. Plus, the rise of body armor made 9mm a lot less effective in the world of modern combat. NATO wanted something the size of SMG that could fire a round more akin to a rifle. They wanted superior range and penetration compared to a handgun round.

This would develop the Personal Defense Weapon, which led FN to create the FN P90 and the FN Five-Seven pistol. This cartridge could penetrate a metal helmet or an IIIA vest out to 200 meters. This all happened in 1991 and guess what? Nothing really happened.

Fiocchi 4.6x30mm ammunition

The 4.6x30mm is younger and hotter, right?

In 2002 NATO remembered they had this project going and decided that turning your homework in late was better than never. However, now the FN P90 wasn’t alone. HK developed the MP7 and the 4.6x30mm round. Experts from the U.K., the U.S., Canada, France, and Germany gathered to evaluate the two.

Who Won?

Well, fair question. Most of the NATO experts agreed the 5.7 was better. It worked better against unarmored targets and equally as good against armored targets. 5.7 could also be produced on 5.56 lines, apparently, and 5.7x28mm was already in wide production.

The Germans said “Nah,” and they cheered on the home team, aka HK, and all testing halted. The project died in 2004. Yet, both the 5.7×28 and the 4.6×30 saw adoption by numerous military and police forces.

In the United States, the Secret Service famously utilizes the P90 in the protection of the president of the United States. SEAL Team 6, aka DEVGRU, aka Osama clappers, field the MP7 for specialized roles. Both guns can be described as successful.

FN P90

My Experience — 4.6x30mm vs 5.7x28mm

I’ve been lucky enough to shoot both cartridges at various range days through some selective-fire weapons. The 5.7x28mm has been used in a variety of firearms available on the civilian market. This includes FN’s own PS90, the Five-Seven pistol, the Ruger 5.7, the DiamondBack DBX, the CMMG Banshee, and more that I’m likely missing.

Navy SEAL with HK MP7

SEALs love the MP7.

The 4.6x30mm has only one platform, the MP7, and HK doesn’t want to bring that to the civilian market. I was just lucky enough to be at a media event with a machine gun section, and alas, there was an MP7.

In my limited time with both calibers, I’ve always been surprised by how light and handy they are. They both have very low recoil and deliver accurate and flat fire out to 100 to 200 yards. A tiny holdover, and at 200 yards, it was dinging steel. They are soft shooting and a ton of fun. I see why people like them. My impressions only go so far though so let’s look at the numbers.

The Energy!

Both of these teeny-tiny fast bullets fly at rifle speeds from SMG-length barrels. Both rounds were designed to kill by tumbling and not expansion. Using JHP ammo of type isn’t a popular option for military forces, so the design made sense for what it was.

Let’s compare like with like to be fair. Keep in mind I’m using the P90’s longer 10.4-inch barrel versus the MP7’s 7.1-inch barrel. A little barrel length makes a fair difference in these calibers.

Marine with HK MP7

Even the Marines caught hands-on with the MP7.

Would the 4.6×30 perform better with a longer barrel? Yeah, probably, but we don’t have anything longer to test just yet.

A 31 grain 5.7 round at 2,350 feet per second has 380-foot pounds of energy behind it. The MP7 launches a 31 grain AP round at 2,410 feet per second and dumps 400 foot-pounds of energy into a target. It’s a slight advantage to the 4.6x30mm.

Max Range

Here the 5.7×28 takes a slight advantage in the 4.6x30mm vs 5.7x28mm, especially beyond 150 yards. The little 5.7x28mm has a 50 feet per second advantage at 150 yards, and the gap grows slightly beyond 150 yards. It’s not a major difference but bears mentioning. At longer ranges, the velocity is maintained and helps it against both armor and barrier penetration.

KelTec P50

Even KelTec makes 5.7 guns.

When it comes to bullet drop, the rounds are almost the same. We are talking fractional differences between the drop as the rounds reach these longer ranges.


I have a hot take when it comes to price when it comes to the two rounds. Right now, if you went to buy ammo, the 5.7x28mm is a fair bit cheaper. This is simply because the market has adopted the round and produced more of it. The economy of scale is on the side of the 5.7x28mm.

FN P90

Stargate approved.

Well, my hot take is that 4.6x30mm could be cheaper if produced in bulk. The 5.7x28mm requires a lacquer to be applied to the cartridges to allow them to feed reliably. That lacquer costs money. If the 4.6x30mm was produced en masse, I think it could be cheaper. I could be wrong, of course, but at the very least, it would be easier to reload.

Personal Defense Purposes?

So who wins in 4.6x30mm vs 5.7x28mm? Both rounds don’t offer the same ballistic potential as good ole 9mm against unarmored targets, and if you wanted a subgun, the 9mm would probably be the best, especially when you factor in training costs, magazines, etc. However, until something comes out in 4.6x30mm, you won’t exactly be able to employ anything but 5.7 in the PDW role.

I think both cartridges are fascinating and would love either— not necessarily for defensive purposes but for predator hunting. I’d love to pop coyotes in the head at 100 yards with a light little blaster. CMMG’s FourSix AR15 building kit allows the 4.6 to fit in an AR platform. Also, how many 4.6x30mm rounds could I fit in a J frame revolver’s cylinder? Can I get seven in a tiny revolver?

Sadly I can’t answer these questions, but I would if I could. Let me know below what you think of these cartridges and which you’d prefer.


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Travis Pike

Travis Pike

About the Author


  1. Hoyt

    I Have an AR-15 configured to take p90 mags feeds from top of receiver and drops brass out of the mag well. I love it. made by ULT.

  2. Val K. Nakahara

    Now that they make AR-15 uppers for the 5.7 with the FN mags, I’d have to give the win to the 5.7.

  3. Bob

    Until the cartridges are not only more available and less expensive, but we get our right to proper AP cartridges back, I’ll stick with 9mm and .45 acp in pistol caliber carbines and submachineguns, and 10mm in my handguns. Except for my M11A1 in .380, and thats an oddball little exception to the rule.

  4. nun yurbyznes

    Cmmg now has a Banshee in 4.6!

  5. Delores Figueroa

    Definitely the 57x28mm that is a bias and highly subjective opinion I hold, just simply (as like you) of the two rds it’s the only one I have enjoyed (the most). I’ve shot tons of 5.7 out of the FN Five Seven (fn57) as well as the 2 ruger 5.7’s I own.
    I also recently took interest in the PS90, the DBX57 and KelTec P50 chambered in 57x28mm. It my preferred EDC round. I know that the looters and criminal minded wear Ballistic vest so I like the idea of being able to outgun the threat.
    Thanks for the well written read and analysis.


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