The beauty of the 5.7×28 FN round is its ability to achieve rifle-like velocity out of a handgun platform. This allows the 5.7 to generate energies similar to standard pressure 9mm Luger ammunition with lighter 27-40 grain ammunition. The 5.7 also boasts less recoil and, with military loadings, is more effective against soft body armor. So who would bother to create a 5.7 loading that slows that bullet down? The answer is Fiocchi.
Fiocchi USA is the primary manufacturer and distributor of FN ammunition in the United States and also puts of 5.7x28mm ammo under their own name. One of their offerings is a heavier 5.7mm 62-grain subsonic load. Given that 5.7 is essentially .22 caliber and Fiocchi’s subsonic load is traveling at 22 Long Rifle velocities, I decided to give it a shot and see how it compared to some recent .22 Long Rifle tests I have done.
The Fiocchi Subsonic 5.7×28 Load
New for 2023, Fiocchi’s 5.7x28mm load is the sole low-powered option available from a major manufacturer. Like other 5.7 rounds, it uses a pointed spitzer bullet, but it is 62 grains in weight instead of the more typical 40-grain bullet found in most loadings. Think about 5.56 NATO 62 grain FMJ ammunition and you will not be far off the mark when it comes to bullets.
The heavier bullet creates more back pressure for a lower powder load in the case, allowing it to cycle in an auto pistol. This load is subsonic with an advertised velocity of 1080 feet per second. A comparable plinking ammo, the Federal American Eagle 40 grain load runs at over 1600 feet per second. The difference comes not only in velocity but also in report. The subsonic load does give the supersonic crack of a bullet going over the speed of sound. Subsonic loads are quieter than conventional ammunition and are especially quiet in suppressed firearms. Fiocchi USA had the latest generation of threaded-barreled handguns like the Smith & Wesson 5.7 and the PSA Rock in mind when they developed this load.
Velocity and Report
I started my testing by shooting some of the Fiocchi 5.7 load over my Caldwell Chronograph from ten feet away. The pistol I used is a PSA Rock with a 5¼ inch barrel. As it happens, it is one of those newer suppressor-ready 5.7 pistols. Although I did not have a suppressor handy, I took this opportunity to gauge the sound of the round and the recoil of the pistol compared to standard loads.
My five-round average velocity with the Fiocchi load was 1052 feet per second. After shooting some more ammunition, I noticed the report of this load to be quieter than something like the Federal American Eagle or FN 27 grain loads I previously tested. When shooting steel targets at 25 yards with this load, I could hear a definite ping when I hit the target. With those other rounds, noise drowned out my ability to hear a hit.
In terms of recoil, the 5.7 round is gentle to shoot, but there was somewhat less muzzle flip with the subsonic load. It also appeared the Fiocchi load was gentle in terms of cycling the action. All 5.7 loads I have tried scatter far and wide when the cases are ejected from my pistol. The Fiocchi load ejects cleanly, landing in neat piles six feet behind me. Recoil, report, and ejection patterns are going to vary with each gun and whether or not a suppressor is used.
Subsonic 5.7×28 Gel Test
The 5.7×28 round is tricky to test in ballistic gel. It does most of its damage by tumbling, rather than expanding like a conventional pistol round. As such, it’s too easy for 5.7 rounds to tumble from that medium and escape. This time was no different.
I set up three Clear Ballistics 10% gelatin blocks fronted by four layers of denim. This represents a simulation of muscle tissue and heavy clothing (or shooting through a clothed appendage first). From a distance of ten feet, I fired four rounds.
Although the Fiocchi 5.7 subsonic load is only traveling at the same speed as high velocity .22 LR ammunition out of a handgun, the longer 62-grain spitzer rounds did outsized damage by comparison. Each of the four rounds tumbled in the gelatin blocks. The rounds left extensive stretch cavities measuring upwards of one inch in diameter between the two to seven-inch mark. By that point, the rounds settled into their final arch. Two escaped the block at the nine-inch mark. Another escaped at 11¾ inches. One round was captured with the base facing forwards. It stopped at 11 inches.
Parting Shots
In another test, I evaluated CCI Velocitor 40 grain and Winchester Hyper Speed .22 Long Rifle hyper velocity loads. Out of a short, barreled handgun, the velocities between these rounds and the Fiocchi 5.7 subsonic are close. Yet whether fired from a short-barreled handgun or a rifle, both .22 rounds could barely hit the 11-inch mark. Both tumbled in the same medium, but the lighter, squat 40 grain round-nosed bullets did far less damage at the same velocity as the 5.7s 62-grain spitzer.
Although penetration is on the lighter side compared to rounds like the Federal American Eagle 5.7×28, the Fiocchi subsonic load did more damage than the .22 LR — and even the .22 Magnum — at the same speeds. While the 5.7×28 shines with higher velocity loadings, the Fiocchi load is gentler and easier to suppress, yet can still be effective on target.
