At 5.7 Fest, various 5.7x28mm loads were fired in Clear Ballistics synthetic gel. Most of the defensive loads, including Fiocchi’s Hyperformance 40-grain tipped hollowpoint, penetrated at least 12 inches.
December 01, 2024
By James Tarr
After languishing as a weird, niche cartridge, interest in the 5.7x28mm has seemingly exploded in the last five years. Unlike the 10mm, though, for which renewed interest seemed to appear for no traceable reason, the 5.7 revival is easily explained.
Since the introduction by FN in 1990 — and until 2020 — there were just two factory platforms chambering in the 5.7: FN P90 PDW for which the cartridge was designed (and the PS90 semiautomatic carbine in commercial form), as well as the FN Five-seveN pistol. The P90/PS90 and Five-seveN pistol were considered expensive, and the ammunition, which was made exclusively for FN by Fiocchi, was expensive and hard to find.
Then, FN’s patents expired. In December 2019, Ruger introduced the Ruger-5.7 pistol at almost half the cost of FN Five-seveN . Surprising to many, the Ruger-5.7 was a hit. Since then, Smith & Wesson released its M&P 5.7 ; KelTec the P50 that feeds P90-type 50-round magazines; Palmetto State Armory PSA 5.7 Rock; and TISAS the Turkish-made PX-5.7 . I’ve also heard that Taurus will be introducing a 5.7-chambered pistol soon.
On the ammo side, the 5.7x28mm cartridge was SAAMI approved on July 11, 2024. In addition to Fiocchi and FN ammunition, even Federal, Hornady and Speer are offering loads for it. It’s finally a mainstream cartridge.
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On May 7, 2024 — “5/7,” get it? — I attended “5.7 Fest” hosted by Gun Talk and Range Ready Studios in Louisiana. It was a two-day event where gunwriters gathered with various manufacturers to talk about all things 5.7x28mm, past, present, and future. It was educational, and I left with a lot of new information. First, let’s revisit history for readers who may be new to this little bottlenecked cartridge.
The 5.7x28mm offers low recoil and fast follow-up shots. Tarr tested the TISAS PX-5.7, and the muzzle remained flat through rapid fire. The FN 5.7x28mm was designed for the select-fire FN P90 Personal Defense Weapon (PDW). The specs for the cartridge called for a round that could penetrate a ballistic helmet at 200 meters while fitting into a gun smaller and lighter than a standard rifle. The 5.7x28mm SS190 cartridge was capable of defeating armor, but since it was “armor piercing,” it was not available commercially. Other sporting full-metal-jacket (FMJ), polymer tipped, and jacketed-hollowpoint (JHP) loads followed in 2000.
Out of the P90’s 10.4-inch barrel, most 5.7 loads will do more than 2,200 feet per second (fps). Current offerings feature bullets from 35 to 62 grains. Except for the subsonic rounds, most cartridges travel 1,600 to 1,800 fps out of pistol-length barrels.
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In appearance, the bottlenecked 5.7 looks like a baby rifle cartridge, which is basically what it is. Because it has almost no taper, the cartridge body needs to be lubricated during the manufacturing process. This was the reason why many ammunition makers were slow to invest in the cartridge, aside from the fact that there were only a few guns chambered for it.
While long, the cartridge cases are skinny, which means magazine capacities for 5.7mm pistols start at 20 and go up from there. Capacity is a big selling point. While it is loud, one of the reasons the 5.7 has been popular in pistols is due to the lack of felt recoil. It has less recoil than a 9mm, and is controllable. The main reasons the 5.7 isn’t more popular as a carry cartridge is due to the fact that the pistols and frames have to be sizable to accommodate the length of the cartridge and SAAMI’s maximum average pressure of 48,500 psi. Several companies are working on smaller versions of a 5.7 pistol, but the long, high-pressure cartridge is problematic when used in short barrels.
On the long-gun side, Ruger offers its LC Carbine chambered in 5.7 , and there are several AR-based pistols, rifles, and conversion kits. At the 2024 NRA Annual Meetings, an FN rep told me it was thinking about offering semiauto short-barreled-rifle (SBR) versions of the PS90 with the 10.4-inch barrel due to the short wait times in the ATF approving SBRs. (I told FN to stop thinking about it and do it!) Having twice watched all 17 seasons of “Stargate SG-1,” “Stargate: Atlantis,” and “Stargate Universe,” where the P90 is so heavily featured it could be considered a co-star, I’d buy one! (Don’t judge me, please.)
While I can’t speak to the specific reason behind the interest in the 5.7 from the U.S. Secret Service, I know why American police departments were initially drawn to it: The common commercial, non-armor piercing loads, don’t penetrate barriers well. The small, light 35- to 40-grain JHPs hit plywood or drywall and fragment. Police departments that answer a lot of calls inside apartment buildings liked the fact that the 5.7mm bullets produced less overpenetration risk than traditional handgun bullets.
Ammo was once rare and expensive, and only made by Fiocchi for FN. The 5.7x28mm round is now more widely available, and much of it was developed for personal defense. Hornady offers a 40-grain V-Max Black and a 40-grain Critical Defense load. Speer engineered a 40-grain Gold Dot load. For those who train a lot, American Eagle sells affordable FMJ bulk packs featuring a 40-grain bullet. At the event in Louisiana, Fiocchi representatives discussed its new 400-round combo and value packs that combine 300 rounds of 40-grain FMJ for practice with 100 rounds of either 40-grain JHPs or 62-grain subsonic rounds.
The bottlenecked 5.7x28 cartridge is slender. Mag capacities are often at least 20. At 5.7 Fest, there were product presentations from Burris, EOTech, Fiocchi, Hornady, Meprolight, Ruger, Silencer Central, Smith & Wesson, Steiner, The Kinetic Group (i.e., Federal and Speer), and TISAS. In addition to shooting a lot of 5.7x28mm through various platforms, we witnessed a ballistic gel test of various 5.7 loads. We also watched a decibel meter test illustrating the efficacy of the Silencer Central Banish 22 silencer on various 5.7 firearms, shooting both super- and subsonic ammunition. Fiocchi’s 62-grain subsonic FMJ load was “Hollywood quiet,” as some like to say, producing just 122 decibels (dB).
Gel tests of 5.7 ammunition were interesting, and I walked away from the event with a new opinion: The 5.7x28mm isn’t a bad choice for personal defense, as long as you understand its limitations.
I know a few people who actually carry pistols chambered in 5.7; I was ambivalent. After 5.7 Fest, I understand the choice. Bullets wound two ways: With permanent wound cavities and with hydrostatic shock, a product of velocity upon impact. Generally, a defensive bullet needs an impact velocity of more than 2,000 fps to produce traumatic hydrostatic shock, which typically means you need a carry a rifle. Out of a pistol, the 5.7mm bullet lives in that nebulous gray area between the two. The bullets speed downrange at near-rifle velocities, and the speed seems to offset the small size and weight of the projectile.
While there haven’t been a lot of shootings involving the 5.7x28mm — there have been some — it seems to perform as well as standard pistol-caliber hollowpoints on the street. A representative from the U.S. Concealed Carry Association (USCCA) attended the event. He stated the organization was currently defending a member who’d used a 5.7 pistol in a shooting. After two shots were placed center mass, the threat stopped, dropped, and died.
Gel testing using Clear Ballistics blocks is not quite FBI spec, but it is close. I saw excellent results. Generally, 5.7mm JHPs will penetrate 12-plus inches in bare gel or gel covered with FBI-spec “heavy clothing.” The velocity seemed to guarantee expansion or fragmentation.
What 5.7x28mm isn’t good at is penetrating barriers, which is why some law enforcement agencies choose it for certain roles: Indoor security and around crowds, for example. The light, fast bullets go through clothing fine, but they usually break apart against drywall or auto glass, and they have a much lower chance of passing through a person. This makes it a reasonable, rational caliber choice for the concealed carry piece of a private citizen who is far more likely to get into a face-to-face confrontation. Let’s not forget: 5.7 pistols, while large, offer generous magazine capacities and relatively low recoil.
Even though the cartridge was introduced almost 35 years ago, it’s only been during the last five years that we’ve seen a lot of exciting opportunities with the 5.7x28mm. From what I learned at 5.7 Fest, I expect we’ll see even more in the coming years.
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