The attention of American shooters was seized a few years ago by FN’s revolutionary new PS90 carbine and the 5.7x28mm cartridge. The subsequent introduction of the Buck Rogers-esque 5.7 pistol was equally noteworthy.
As much as people talked about FN’s new introductions, I must confess that neither of the unusual-looking blasters really blew my skirt up. To be frank, I wasn’t too excited about those tiny 28- and 40-grain projectiles for self-defense either. But a few positive reports about the cartridge’s performance and chance encounters with friends’ PS90 carbines and Five-seveN pistols made me take a closer look at FN’s diminutive duo.
The PS90 Carbine
FN’s P90 submachine gun and 5.7x28mm round were developed in 1986-1987, though it took more than a decade to go from concept to production for the civilian market. The P90 was designed as a Personal Defense Weapon (PDW). FN’s P90 found favor with soldiers who operate in tight spaces like vehicles and aircraft. In that role, it is a very practical piece. But collectors don’t give a lick about practical; they dig the P90′s looks and revolutionary new features. FN introduced the civilian-legal version, dubbed the PS90, to satisfy that demand.
The semiautomatic PS90 is a straight blowback design with an integral optic. Because it is a conventional blowback design, the bolt group is quite substantial. The bolt reciprocates against a pair of springs that surround a pair of steel guide rods, which fit into recesses in the barrel-support group for smooth, solid operation. The 161⁄16-inch barrel is hammer-forged and chrome-lined, and it has a muzzle brake with six ports.
One of the PS90′s most noteworthy features is its unique, horizontally mounted, polymer magazine that sits above the barrel, parallel to the bore axis. Its position necessitates an unusual magazine design that stores cartridges perpendicular to the bore.
The rounds are loaded conventionally, but inserting the second round rotates the first cartridge clockwise approximately 80 degrees within a spiral chute. The third round moves the first round to a 90-degree angle to the bore axis, and subsequent rounds make their way into a staggered-column configuration. The loaded magazine is slid into the receiver/barrel-support group from the rear and is locked into the magazine opening with moderate downward pressure.
As the bolt’s forward movement strips a round, the next cartridge instantaneously twists around the chute and into position. The last two “rounds” are actually nylon rollers that can be removed only while disassembling the magazine. An internal block reduces the capacity of the PS90 magazine to 30 rounds instead of 50 as in the P90.
One safety note on the PS90: Remove the magazine before operating the charging handle to clear and safe the gun because the magazine makes it impossible to see the breech. The ambidextrous magazine release is on top of the buttstock.
An integral optic was mounted atop the receiver/barrel-support group of the PS90 USG that I received. It is a zero-magnification reflex unit intended for fast, close-in work. Its reticle has a circle with a dot in it and three black posts that glow red in low light thanks to a little tritium. The reflex sight of the USG can be removed and replaced with an adaptor for use with other optics. The PS90 TR (Triple Rail) is available with a Picatinny rail instead of the standard reflex sight.
The cocking handle is a low-profile, ambidextrous affair that is easy to manipulate. The bolt does not stay open after the last shot.
Even though it is a bullpup, I was pleased to see the PS90′s trigger pull come in at a respectable 7 pounds, 10 ounces, with minimal mushiness. The rotating safety is mounted just below the trigger.
Unlike most bullpups, the PS90 ejects its empties out the bottom. That, combined with identical controls on both sides of the gun, makes the PS90 a truly ambidextrous fighting gun.
Bullpups shine in tight spaces thanks to their short overall length. By placing the bolt group and breech next to the shooter’s face and the trigger forward, it is almost impossible to make an unwieldy bullpup. With its 161⁄16-inch barrel, the PS90 is just 26.25 inches overall. That makes for a handy home-defense or car gun.
The Five-seveN Pistol
The Five-seveN pistol is the most futuristic-looking pistol I’ve ever tested. But beneath its ray-gun appearance, the PS90′s little sibling is a pretty conventional delayed-blowback design. Although the back of the slide gives it the appearance of being striker-fired, the Five-seveN actually has a conventional single-action trigger. The hammer is concealed by the back of the slide.
The Five-seveN also has the appearance of being made completely of some high-tech polymer. While the checkered frame is indeed molded from polymer, the polymer on the slide is just a cover; underneath, it’s solid steel. Molded-in ridges at the back of the slide provide a secure purchase for slide manipulation. A fixed front sight and a fully adjustable rear sight provide an excellent sight picture. Brilliant white dots fore and aft help align the sights in any light.
The Five-seveN’s frame has checkering molded in to the sides and striations on the front and rear of the grip. A slight finger groove is also molded into the frontstrap. The dustcover features an integral Picatinny-spec accessory rail for mounting lights and lasers.
The reversible magazine release stands proud in the usual location, and the slide release is perfectly positioned for easy activation with the strong-hand thumb. The disassembly button is located on the left side of the gun at the front of the dustcover. The ambidextrous, low-profile safety lever is unconventionally situated just above and slightly ahead of the trigger. Up is “Safe.”
My gun came with three 20-round magazines, though 10-rounders are available for those living in less gun-friendly locales. The Five-seveN has a magazine-disconnect safety, but fortunately, it doesn’t affect the pull weight or feel of the trigger as some other designs do.
A stainless-steel loaded chamber indicator is positioned atop the slide, to the left rear of the ejection port.
The Five-seveN’s stainless-steel, 43⁄4-inch barrel is hammer-forged, and a captive recoil spring surrounds the barrel. A fixed, flat guide rod is mounted to the dustcover. The Five-seveN’s two tiny slide rails are mounted at the back of the frame. They measure just .4 inch, but the Five-seveN’s slid
e reciprocates smoothly along them.
The test unit’s trigger pull had a bit of take-up and broke at a respectable 6 pounds, 11 ounces. Overtravel was minimal. It wasn’t comparable to a really good 1911 trigger, but it wasn’t bad.
My first impression of the Five-seveN was that it is a well-made pistol with some interesting features. I was anxious to get it and the PS90 out on the range for some accuracy and reliability testing.
On The Range With The 5.7s
I did my reliability testing with both guns over one extended shooting session because I knew the 5.7x28mm’s recoil was light enough that fatigue wouldn’t be an issue and because I needed the brass so I could develop a few handloads for my accuracy testing. So I packed up a ton of FNH USA ammunition and headed to the range to make some brass.
I started by loading up the PS90′s 30-round magazine. I had a hard time getting the magazine started at first, but once I got used to it, loading the unusual magazine was pretty simple.
Though it looks like a toy and is very lightweight, the PS90 is a serious shooter. The trigger was pretty good for a fighting gun, and the little bullpup came up the shoulder quickly and easily. The optic was easy to acquire quickly with both eyes open, despite my cross-dominance, though I felt the field of view is a bit too narrow.
I’ve shot a few PS90s, so I wasn’t surprised by just how much fun the little carbine was to shoot. It was very accurate, and there was almost no recoil, so accurate follow-ups came fast and easy.
Likewise on the Five-seveN, recoil was non-existent, so it was easy to dump magazines. No matter how fast I pulled the trigger, the pistol fed, fired, and ejected perfectly, and my bullets found their mark more often than not.
The single-action trigger was clean and felt lighter than my trigger-pull gauge indicated. The three-dot sights were easy to acquire and zeroed perfectly at 25 yards with FN’s 40-grain load. All controls worked smoothly and positively.
Accuracy-Tesing The 5.7x28mm
I ordered dies from RCBS so I could work up some handloads for the test guns. Unfortunately, the guns came in so close to deadline that I didn’t have a lot of time for load development. I restricted my extensive accuracy testing to two factory loads and my two best handloads.
I started with two FN factory loads: the SS195 load with a 28-grain lead-free hollowpoint and the SS197 load with a 40-grain V-Max bullet. Both factory loads produced very consistent velocities from both guns and shot well. As I expected, given the fast rate of twist in both guns’ barrels, they preferred the heavier 40-grain offering. However, I would caution against the temptation to load bullets heavier than 40 grains in either gun, as they could generate too much pressure for the blowback-operated guns to handle.
My handloads shot fairly well overall, though the PS90 really liked the 40-grain Sierra SP over a little less than the max charge of Accurate No. 7. This load left the muzzle of the PS90 at 2,342 fps, and it averaged 1.82 inches for five, five-shot groups at 50 yards. This load is fast and accurate enough, and the bullet is tough enough, that it is the one I would choose were I to use a 5.7x28mm for varmint hunting.
Overall, the PS90′s accuracy was very good, though I do not believe I came anywhere close to wringing the utmost accuracy from the little carbine because of the zero-power optic. The sight worked well for fast, up-close work, but a little magnification and a smaller reticle would have helped me shoot small groups out to 100 yards. As it was, the dot obscured the bull at 50 yards.
The Five-seveN pistol was extremely accurate. In fact, I don’t think I’ve ever tested another pistol as adept at smoking small varmints, rocks, and tin cans out to 100 yards and beyond. I was so impressed with its accuracy that I plan to do some more load development before it goes back to FN.
The Last Word
I know I wasn’t excited by the introduction of FN’s PS90 carbine, Five-seveN pistol, and 5.7x28mm cartridge. But after the time I spent working with them recently, my opinions have changed.
I am still not completely sold on the 5.7x28mm cartridge for self-defense; however, as a plinking and varmint cartridge, the 5.7x28mm is the cat’s pajamas. In fact, I plan on building a bolt gun chambered for it in the near future.
The Five-seveN pistol is a well-made, accurate, and very reliable pistol. It is a heck of a flat-shooting piece also. I’d love to have one for plinking and busting varmints. But with its integral accessory rail and 20-round magazine, it would make a heck of a defensive piece, too.
Great handling, super accuracy, unwavering reliability, and light recoil combine to make FN’s PS90 one of the most fun guns I’ve tested in a long time. And thanks to its cool new round, unusual magazine, and true ambidextrous operation, it is also one of the only truly revolutionary guns I’ve ever tested. I was so impressed with its performance and features, I am considering ordering the TR version so I can mount a different optic on it. So equipped, I can see it replacing my .22 Hornet as my ranch rifle. I can’t think of any higher praise than that.