The FNH PS90: What Is It, and What Does It Do Well?


by Frank James

photography by Frank James

July 30th, 2007




Compared to the sporting arms market, the introduction of a new military small arm cartridge is a rare event and somewhat on the order of a panda getting pregnant at the Washington D.C. Zoo, or a politician at that other zoo in Washington convicted of telling the truth.  In this world of NATO standardization a new service cartridge just doesn’t happen all that often and it’s even more unusual now that many of the former eastern European countries are adopting NATO standard small arms and ammunition while abandoning their former Communist origin arms and calibers.  Therefore it was more than noteworthy when FNH of Belgium responded to a NATO request proposal for a new class of “personal defense weapon” during the late 1980’s and early 1990’s by introducing a gun to meet the specifications with their P90 and its 5.7x28mm cartridge.

NATO felt there would be increased use of protective, flexible body armor by the military of all nations in the decades to come and therefore called for this new class of individual service weapons.  I was fortunate during a European trip in 1993 in that I was allowed to test the new selective-fire weapon designed for this round -- the P90 at FN’s test range near Herstal, Belgium. 

The P90 is something of an odd military small arm.  It was never designed to be a standard military service rifle, but was actually designed as a weapon for rear echelon troops like motor pool mechanics, drivers, cooks and bakers as well as a special purpose weapon for troops engaging in close quarter battle.  The idea behind it is previous pistol caliber weapons; i.e. pistols and submachine guns, were becoming increasingly ineffective against issued protective body armor while standard service issue assault rifles were too heavy or unwieldy for either rear echelon troops or for use in close quarter battle scenarios. 

Because of its new cartridge the FNH P90 can’t truly be classified as a submachine gun, but then it really doesn’t qualify as a traditional assault rifle either.  One of the design characteristics of the P90 and its associated 5.7x28mm round is the fact it was designed from the get-go to have a limited range.  Yes, the ammo was designed to defeat both soft and some hard body armor, even some of the heaviest in use by former soviet military forces, but it was also designed to have a limited lethal range.  It was not meant for long range use.  I was informed in Belgium back in 1993 that it had a practical range limit of approximately 150 meters.  Testing on the civilian legal ammo available with the semi-auto test sample shown here indicates it is good to 200 yards, but that is probably its absolute practical limit.

OK, over a decade has passed since the gun and cartridge’s introduction and the only thing that can be said is the obvious.  It has NOT proven to be an overwhelming or revolutionary design.  Whether this will change in the future remains to be seen, but the world has NOT beaten a path to FNH’s door demanding vast quantities of these weapons or this cartridge.  Yes, some FN P90 carbines were used by the hostage rescue teams like the well known rescue event during an embassy siege in Peru, but overall its acceptance and success has been one of a limited nature.  Rumor has it that Saudi Arabia has purchased a substantial number, but other foreign sales have been limited at best.  There are some American law enforcement agencies, including Secret Service protective teams, equipped with the gun on their tactical units and the operators sing their praises on various web sites, but the gun and its cartridge are not without their critics.

All of this is important to keep in mind when one starts examining and reviewing the civilian legal version of the FNH P90, the FNH PS90.  Especially so when one understands from the very beginning the ammunition this design concept was originally developed around is forbidden to civilians.  It is the first example in my memory where the ammunition; specifically the SS190 round is classified the same as select-fire weapons or sound suppressors.  The armor piercing ammunition is a Class III item in and of itself.

Then the question becomes: what is the civilian legal version of the P90, or the PS90, good for?  What purpose and what role does it serve in the civilian sporting arms market, other than the obvious, “Gee, it sure looks really neat??”  And how good is the civilian legal ammunition?  What will it do and what will it not do?


When I tested the prototype P90 in Belgium back in the early 1990’s there was a problem with the ammunition.  The ammunition used during my test session, I was told, consisted of a 23 grain full metal jacket projectile with a plastic or polymer core.  The problem was, and I observed it firsthand, resulting two groups on the 100 meter paper target from either semi-auto fire or full-auto fire.  The main group was more or less point of aim/point of impact and the second group (approximately one third of the rounds fired) was found roughly four inches to the right and four inches high from the point of aim group.  At the time they didn’t have an answer for this problem but admitted it was a serious concern.  In 1994 this round was abandoned in favor of the heavier SS190 projectile with its steel penetrator and aluminum core.  It is strictly a guess on my part, but the dispersion problem had to be part of the reason why the lightweight 5.7x28mm projectile was discarded.

That is a shame really because it is my view the lighter projectiles with this combination of the PS-90 and the 5.7x28mm could provide the civilian centerfire competitor with a combination not found with any other centerfire gun and cartridge combination currently available. 

Why is this important?  Because it is easy for most civilian shooters to find places to shoot their handguns and shotguns in competition in just about any location you care to mention in this country, but it is becoming increasing difficult to find a venue where it is safe to shoot centerfire rifles and carbines.  We are desperately short of rifle ranges in America, square range or otherwise, and it is even harder to find a range where you can have an action oriented centerfire rifle/carbine competition without the issue of ricochets and wayward over-the-berm rounds compromising range safety.

During my testing of the sample PS90 I used two specific 5.7x28mm rounds; the SS195LF (lead free) and the SS197SR (sporting round) with a blue polycarbonate Hornady 40 grain V-Max bullet.  Other rounds available at one time or another in 5.7x28mm, but not used in this report, include the SS191 Tracer which has a trajectory identical to the SS190.  This round is identified by a painted red tip on the projectile.  The discontinued SS192 hollow point round which used a 28 grain unmarked projectile and is distinguished from the SS195LF by the use of a brass colored primer, the SS193 sub sonic round which employs a 55 grain Sierra FMJ-boat tail bullet and was designed for use with a sound suppressor.  The discontinued T194 round which is identified by a painted green projectile tip and a silver colored primer and was used as a training round until being replaced by the SS192 and SS195 rounds, and the discontinued SS196SR which used a red polycarbonate Hornady V-Max 40 grain bullet.

The criticism of the 5.7x28mm cartridge centers around the question of its stopping power or whether it will stop an armed antagonist.  Dr. Martin Fackler was an early critic of the round when he postulated it was little more than a centerfire version of the .22 Rimfire Winchester Magnum round.  Since the ability to defeat soft body armor is legally denied by authorities at various levels to civilian shooters, one has to seriously ponder the terminal ballistics of this small centerfire round with the ammo available.

Most of the test data that has been published has almost always employed the civilian-prohibited SS190 round and its performance is questionable at best.  The current FBI standard for projectile penetration depth in 10% gelatin is twelve inches, but published test data from tests by the Royal Canadian Mounted Police Academy forensics lab indicates an average depth of only 10.4 inches.  Dr. Gary Roberts has tested the P90 with the SS190 ammo and found his results averaged the minimum of twelve inches in 10% gelatin.  Anecdotal reports involving actual shootings by law enforcement special response officers armed with P90s range from instant incapacitation to incidents where the perpetrator stopped his criminal behavior but complained about being shot five or six times from the full-auto fire.  Obviously, the issue is uncertain as this round’s ability to stop enraged criminals cold in their tracks has yet to be demonstrated on a regular basis.

The prudent civilian should examine alternative cartridges and carbines if they are searching for a tactical carbine for home defense and select one with a better reputation for finalizing unwanted criminal behavior.  For applications outside the lethal force arena, the gun may very well prove ideal with its low felt recoil and limited range, but I have yet to use it on anything walking or crawling across my farm, so my personal final verdict has yet to be delivered.


The shape and overall outline of the FNH P90 and PS90 is unique and looks for all the world like something out of a sci-fi film.  It is a bullpup design in that the operating mechanism is located well behind the trigger.  Although the gun has a significant retail price (in excess of $1,600 depending upon the retailer) it uses a large amount of polymer components as well as a cast aluminum receiver so I believe it is not as an expensive gun to manufacture as what FNH would like everyone to believe.

Two features characterize the FNH P90 and PS90.  The first is the horizontal magazine that lays inline with the action and over the barrel and the second is the shape of the forward handguard.  The latter feature is curved and looks for all the world like something taken off a musical instrument.  The designers went to great lengths to guarantee a completely ambidextrous firearm as the gun works equally well for either right or left handed shooters.

It is described in various journals and publications as a blowback operated firearm in that the barrel is not locked to the action.  But, there is a key characteristic everyone is failing to note, and that is upon firing the PS90 barrel MOVES.  Granted, it is a small movement, approximately 0.030 of an inch, but it moves none-the-less and a key definition of any recoil operated firearm is the barrel MOVES.  The barrel must move to maintain safe chamber pressure until the bullet, like Elvis, has left the barrel.  For a round that many classify as a pistol round it operates at relatively high pressure, somewhere around 50,000 psi.  Hence, the need for some mechanism to guarantee everything stays connected until Elvis has left the building.

The PS90 comes with either an olive green plastic body or a black plastic body.  (I’m sure all the drugstore commandos will scarf up the black ones because they are limited in number and look so radical.  I hate to shake their fantasies, but black objects show up easier in low light conditions with night vision devices, so I’ll stick with the olive green version, even if it isn’t as cool looking.)  This plastic body consists of two halves which are bolted together and form the chassis (the frame and trigger group, item #1) which carries (item #2) the barrel support and optical sight group, (item #3) the moving parts group, (item #4) the hammer group and (item #5) the magazine.  There is a great deal of similarity between the layout of the P90/PS90 and the much older Steyr AUG that must be recognized and acknowledged.

The magazine holds fifty rounds when used by the P90, but the test PS90 came with a fifty round magazine that was blocked to thirty round capacity.  The question is...why?  Unfortunately I can’t provide an answer, but you can find a nifty little replacement follower for a reasonable price that will substitute for their elongated block and you will regain a full fifty round capacity with the supplied magazine. 

The ammunition lies cross-wise to the bore-line in the magazine and at the final moment prior to feeding is turned ninety degrees by the magazine feed lips.  It is a curious arrangement, but one that works well.  The magazine body is a smoky translucent polymer which some feel is a real big deal in that you can see how many rounds are in the mag body, but experience with other guns and magazines offering this feature reveals it is of limited value.  The big problem with these magazines seems to be the method of carry for the spare mags as the improper carry can cause rounds to spill from the magazine.  FNH provides a rubber cup for each spare mag to prevent this from happening on their military P90 mag pouches.

The trigger pull on bullpup designs is usually heavy and hard to distinguish and the PS90 stays true to form in this regard.  It is heavy, too heavy to measure on my RCBS trigger pull scale which goes up to six pounds and the action or motion of the trigger is mushy.


In all my years of working with hand held firearms, I have never encountered a more difficult to use and poorly designed piece of sighting equipment as that found with the MC-10-80 Ring Sight reflex sight which is mounted on the PS90 and P90.  In my opinion it has to be one of the dumbest ideas ever sold to a firearms manufacturer; major or otherwise.  If that statement makes me out to be an opinionated, prejudiced, narrow minded son of a you-know-what, so be it.

I ask you; who would use a white colored reticle on a reflex sight for climates well north of the Tropic of Cancer?  In bright daylight it washes out.  Against any kind of light background such as a white building, it washes out.  It will wash out against a well lit cloudy sky and by ‘wash out’ I mean it just flat disappears.  I just can’t imagine how this thing would work in a snow covered field or snowy backyard in the dead of winter.

To be fair, there is a PS-90 variant which uses a black ring reticle, but one has to ask why the black ring isn’t the model being usually shipped and the white ring Ring Sight the optional product?

The reticle seen with the Ring Sight reflex sight consists of a white colored outer ring that approximates 180 MOA and inside it is a smaller white colored ring representing approximately 20 MOA and inside that at the center is a single white dot which is 1 MOA.  In low light conditions there is a horizontal bar on either side of the center dot and a vertical bar below it that becomes visible and creates something of a “T” shaped reticle aiming system.  I found the white colored lines turned to a pinkish rose color in low-light conditions, but the acquisition time for my eyes was not what I have experienced with traditional red-dot sighting systems, whether they were battery powered or tritium.  In short, I found this sighting system extremely inadequate by any measure one would choose to evaluate its performance.

A better alternative is offered by Halo Manufacturing (web site: and it is called the TriRail.  I know FNH is offering a three Picatinny rail version of the P90 and PS90, but the truth is I feel the Halo Mfg. TriRail is a better product.  Once a Picatinny rail is substituted for the horrible Ring Sight, then the question is whether you mount a red dot sight or a traditional cross-hair scope sight in its place.  An option I feel that should have been offered in the very beginning.

Even with the horrid factory installed Ring Sight; there is a crude alternative with a u-notch and post on either side of the Ring Sight as part of the base mount for the Ring Sight.


Testing consisted of a number of informal range sessions shooting tubular objects such as empty adult beverage cans on a regular basis at short range and one formal range session at 100 yards on a square range.  The square range session revealed the SS197SR ammo to be capable of five round groups measuring right at an inch, center-to-center.  The SS195LF ammo was not nearly as accurate as the best group with this stuff just made three inches in diameter.  A better trigger and a better sighting system would have, without question, shrunk these groups by a considerable measure.  Still I have hopes for the device once a better sighting system is installed.


I must confess I purchased the test sample, which I don’t do all that often anymore.  Simple human greed was one reason why I purchased this gun, because if the Democrats win the major elections in ’08 it is a virtual certainly the PS90 will be prohibited from future sales and I believe that makes this purchase a good investment because years later it will double, triple or gain equity at an exponential rate.

Secondly, I believe there is merit to the cartridge and gun combination for civilian applications if the suitable lightweight, limited range ammunition is ever developed.  We as a shooting society truly need some sort of carbine for competition that can be safely fired on most all outdoor pistol ranges.

Thirdly, the magazine holds fifty BBs.  Granted, they are small, underpowered BBs, but there are fifty of them none-the-less and no one knows just how important that may prove in future years and situations.

Is this gun and ammo combination worth the exorbitant price?  You will have to answer that question for yourself as I did for myself.  The FNH PS90 is not a perfect design by any means but it remains an interesting one and that alone may be its most endearing feature.

Frank W. James




Manufacturer:  FNH USA, LLC, P.O. Box 697, McLean, VA 22101

                          Tel: 703-288-1292



MECHANISM TYPE: blowback operated, semi-automatic bullpup carbine

CALIBER: 5.7x28mm

OVERALL LENGTH: 26.2 inches

WEIGHT: 6.4 pounds empty, 7.5 pounds when fully loaded w/50 rounds

BARREL LENGTH:  16.04 inches

RATE OF TWIST: One turn in 9 inches

MAGAZINE CAPACITY:   30 rounds as shipped, 10 rounds for those states that restrict magazine capacity


Got something to say about this article? Want to agree (or disagree) with it? Click the following link to go to the GUNBlast Feedback Page.

Click pictures for a larger version.


The PS90 breaks down easily into the frame & trigger group (shown here at the top), the barrel support and optical sight group (next down), the moving parts group (shown here in the middle), the hammer group (shown here as the gray box below the moving parts group), and the magazine (seen here at the bottom left of the photo).



The PS90 is a semi-auto civilian legal derivative of the FNH select fire military and law enforcement P90 bullpup carbine.  It chambers the 5.7x28mm cartridge.



The fire selector is the only external safety and it has two positions; SAFE and FIRE.  It rotates horizontally.  Internally the PS90 has a safety which blocks the sear should the gun be dropped that prevents an accidental discharge.



One of the distinguishing characteristics of the PS90 is its horizontal translucent polymer magazine that lays inline with the barrel.



The author feels the MC-10-80 Ring Sight reflex sight with its white colored reticule is the worst sighting device he has ever experienced on any small arm.  Against any bright or light colored surface or background it washes out and the aiming point disappears.



Many of the features of the PS90 are ambidextrous, like the cocking handle shown here.



Because the cartridges lay crosswise in the polymer magazine, the feed lips on the magazine must turn each round ninety degrees prior to feeding.  The author reports it is a system that works well.



The author used two different 5.7x28mm rounds during the testing of the FNH PS90, the SS195LF ammo (seen here on the left), and the SS197SR ammo (shown here on the right). The SS197SR was the more accurate of the two.



The 5.7x28mm grew out of a NATO RFP issued in the late 1980’s.  Shown here for comparison purposes is a commercial 9x19mm hollow point round (far left), the SS195LF round, the SS197SR round and finally on the far right a 69 grain 5.56x45mm military rifle round.



The PS90 ejects the fired case out the bottom of the stock.  This ejection port within the stock is equipped with a dust cover that is shown here in the closed position.



Should the optical sight fail, the PS90 is equipped with a crude form of iron sights.  Shown here are the rear u-notch sights on either side of the optical sight mount.



This is the front sight blade for the iron sights, found on either side of the optical sight mount.