The 9x19mm NATO cartridge just seems like a fact of life today. I don’t mean to say that ungratefully, really, but it’s an undeniable force inside the firearms world. Yet, this favored child was once put on the chopping block of history by no less than NATO itself – well, to the extent a bureaucratic design request really spells doom for the status quo. 

But that begs the real question, “Why?” Certainly, the 9mm round has proven itself effective enough for most modern militaries and law enforcement agencies. It’s practical, common, controllable, and functions well in the modern lineup of semi-auto pistols. So, what did the 9mm do to give NATO cold feet?
 

Fever Dreams From the 1990s

 

Luckily, 5.7 ammunition continues to develop, with more and more options for both ammunition and firearms today. (Photo: Chris Eger/Guns.com)


If the 1990s offered anything, it was plenty of promises and some disappointments that hopefully paid off in the end. The 5.7x28mm was a dreamer’s cartridge in the 1990s, though it did just make the list as a NATO-standardized round in 2021.

No matter how good you make something like the 9x19mm, someone is always going to ask for more – more range, velocity, terminal performance … also, why not add in cross-platform options for cutting-edge pistols and carbines? That’s a tall order. There were a few 9mm carbines that tried to do that. But NATO was also interested in defeating the rise of early body armor in the 1980s and 1990s. 
 

The rise of body armor greatly impacted small-arms research, though armor continues to develop even greater stopping power. Here, Marine Gunnery Sgt. Shawn M. Dempsey holds up the small-arms protective insert that saved his life in Iraq in 2006. (Official U.S. Marine Corps Photo)


Gone were the days of “steel pot” helmets and simple combat uniforms. Heck, you would think the modern soldier’s loadout would have been getting lighter with the rise of all these new technologies. But we turned that math around and found new ways to carry even more "lighter" things. 
 

The FN Five-seveN pistol provides 20+1 rounds of 5.7 at the ready. (Photo: Jacki Billings/Guns.com)

That was one of the issues with 9mm. Where 5.56 allowed a soldier to carry nearly twice the ammunition for the same weight as 7.62x51mm NATO, 5.7x28mm promised a similar solution inside a pistol-sized round with greater reach, extra punch, and easier logistics across multiple platforms. Hence the purpose-built pairing of FN’s P90 and the Five-seveN pistol.
 

While the FN P90 magazine held a whopping 50 rounds, even the FN Five-seveN pistol sports standard 20-round magazines (Photo: Chris Eger/Guns.com)


Thus, the NATO search for a personal defense weapon that offered power, accuracy, flat-shooting trajectories, and compactness continued to give some life to the 5.7x28mm chambering. It did this even as some major Western powers snubbed the round – notably Germany, which also had some stock in the competing HK 4.6x30mm and the legacy German 9x19mm Parabellum.
 

Going Ballistic With the 5.7

 

Austrian Special Forces train with the P90. (Photo: Austrian Bundesheer)


The U.S. 5.7x28mm patent application was granted in 1991 to Belgium’s FN Herstal, with credit going to the inventors Jean-Paul Denis and Marc Neuforge. After some NATO trials from 2002 to 2003, the 5.7 came out looking pretty shiny. It was controllable, and it offered more effective impact on protected and unprotected targets over the competition. It was just not shiny enough to get the NATO allies on board with shifting their long-standing pistol caliber away from 9mm.

Still, the 5.7 round and accompanying platforms made their way into the hands of an assortment of military and security organizations around the world – including the U.S. Secret Service and anti-terrorism units. Why not, really, with 50 rounds of high-velocity 5.7x28mm on tap in a compact gun that runs like a buzzsaw?
 

Other PDWs have also seen limited use inside the U.S. military, with a Marine here firing the P90’s challenger, the HK MP7 in 4.6x30mm, while training for embassy reinforcement in 2016. (Photo: U.S. Marine Cpl. Clarence Wimberly)


The ballistic potency of the smaller, bottlenecked round flying at very respectable velocities well in excess of 2,000+ fps – pushing 3,000 depending on the platform – offered a unique ability to blend pistols with PDWs that offered increased effective ranges. 

As appealing as that power was, the sheer advantage in capacity, weight, and cross-platform capabilities make the round scream for a second look as a military chambering. 
 

Even the top-feeding magazine developed specifically for the P90 showed incredible innovation and offered 50 rounds. (Photo: FN Herstal longitudinal magazine patent)


It’s also hardly the first bottleneck pistol-caliber chambering to be considered for military applications, with the 7.62x25mm Tokarev and the earlier 7.63x25mm Mauser earning honorable mention for pushing that envelope. Hotrod pistol rounds have been around for a while, but the 5.7x28mm brings them into the 21st century. FN's guns and the 5.7 ammunition may have offered better performance and capacity, yet the round was still rebuffed by NATO.
 

The much older bottlenecked 7.62x25mm Tokarev, center, predates the 5.7 by multiple generations and a few wars. (Photo: Paul Peterson/Guns.com)


In fact, the round was obscure enough for the U.S. Patent Office to consider 5.7 – even pronounced with FN’s “five-seven” – to be fair game for competitors to use as recently as 2020. Hence, you won’t find many shooters or marketing ads pronouncing the new Ruger-57 as the “Ruger fifty-seven.” For their part, the civilian market may be on the road to embracing the 5.7 more than ever. A wave of new firearms chambered for the cartridge have hit the market in recent years, with even the big-name gunmakers weighing in on the trend.
 

Where Is the 5.7 Going Now?

 

New and interesting guns are coming out chambered in 5.7x28mm, such as the brand-new KelTec P50. It uses the same mag as the FN P90 and would feature well in the next “Star Wars” movie even if it won’t help Storm Troopers shoot better. (Photo: KelTec)


So, is the 5.7x28mm here to stay? It would certainly seem so, with new guns and a growing horde of 5.7 enthusiasts. It may have taken quite a bit of time, but the 5.7 is finally part of the NATO family with the likes of 5.56. If you love the 9mm, don’t fret. It isn’t going anywhere fast. For one thing, the U.S. military just adopted a brand-new 9mm handgun. But the 5.7 has some warfighting potential that might still give it legs after the new NATO adoption and growing civilian interest.
 

The potency of the 5.7 round makes it an increasingly popular chambering for smaller carbine-sized guns like the new Diamondback DBX 5.7. (Photo: Chris Eger/Guns.com)


It seems there were good reasons the futuristic 5.7x28mm and assorted firearms captured the attention of Hollywood back in the 1990s and 2000s. For one thing, the zippy new round also came with some fantastical-looking new firearms, like the P90 of "Stargate SG-1" fame – Notably, it replaced the show’s 9mm MP5 that “performed poorly” against alien body armor. Happily, the lineage looks like it will continue to grow.
 


Banner photo: Francis Flinch, via WikiCommons, released to public domain.

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