Odd Guns: PS90 SBR

If there ever was a gun that you could use as the poster-child of being aesthetically odd, the P90 and its semi auto counterpart, the PS90 certainly would be very strong candidates. The bullpup design of FN Herstal’s P90 make it look like a science fiction throwback, but if a consumer can get past the odd appearance of the system then they really are getting a fun shooter. The subject of this review will be a semi automatic only PS90 that is a registered short barreled rifle. I would love to have a select fire one, but unfortunately the conversion parts are hard to come by.

Anyways, as stated the PS90 just looks strange:


I ditched the factory rail on top and put a mini ACOG mount on top that I bought from TROS USA.


I also added a Gemtech G5 suppressor adapter, but suppressing 5.7x28mm is not at all effective due to the velocity of the round:


Loading magazines for the PS90 is also odd. You push round into the mag as they rotate 90 degrees to stagger into a column of 50:


Also, hitting the range with a PS90 will certainly turn heads, and older folks gawk at how us young guys bring out such bizarre shooters when you start up some friendly banter.

This range day I sighted in the mini ACOG at 20-25 yards:


And I must say that I love this optic!


Shooting five rounds at a time at this distance I painstakingly got the gun to hit where I wanted:


On my last group I got it dialed in just a tad low at this distance, which is where I wanted:


After this initial sight-in day it was time to hit the outdoor range to run the gun a little harder. For this I made a video. I apologize in advance for the wind noise folks:

After a range session, cleaning the PS90 is a breeze. You simply press this button and pull the receivers apart:


After this, pull out the bolt and you are done. You can of course remove the trigger group but this is optional:


As for my overall impressions of the PS90, I think it is an absolutely excellent blaster and smile producer. The low recoil allows you to put rounds on target rapidly and with ease, but the unconventional ergonomics and hand positioning may turn some people off of this firearm. Having 50 rounds available to throw around is also an awesome feature, but I am struggling to find a use for this firearm other than range toy. With selective fire capability I would mount it on a rack above me in my hunting side by side, but as a semi I really do not have confidence that I could take down a feral hog with this gun. I also would not use it for home defense because I fear “militant homeowner shoots misguided robber with souped up uber assault gun” or at the very least having my gun taken as evidence and not getting it back for a long time. As a result, this gun is a range queen, but hey, I am content with that!

Thank you for reading. Stay tuned for more odd guns!

Alex C.

Alex is a Senior Writer for The Firearm Blog and Director of TFBTV.


  • KestrelBike

    FN should just sell the PS90 as a pistol. Not their fault if people place the back of the gun into their shoulder.

    • Esh325

      How exactly would they do that?

      • FourString

        That’s the joke.

    • They would need to do something about the forward grip to be exempt from AOW status and try to pass off a more flattened butt pad as totally not a rifle stock.

      • Will P.

        It’s not a forward grip, it’s just a “trigger guard” lol

        • DIR911911 .

          I don’t see any grip . . .(looks away whistling)

      • Michael R. Zupcak

        Just put big metal spikes on the back saw off the front grip. Who’s going to shoulder a stock with big metal spikes sticking out of it?

  • BattleshipGrey

    Any gun you use in a HD incident can be seized as evidence by the investigating authority, so you should use the most suitable gun you own to defend your life. If it happens to be a really expensive gun, then it’s still money well spent even if it gets seized. If you have to go to court, I’d ask for a jury trial. People may not like your gun, but they can probably appreciate what you did with it.

    • Kurt Akemann

      You’re right about that first part, but the second is a bit iffy. Juries are always a gamble and it is possible to end up with a hung jury because the prosecutor convinced 1 or 2 jurors that your use of a modern semi-auto rifle proved you have a “Rambo mentality”.

      • Grindstone50k

        What percent of home defense cases are brought to trial requiring a jury? Locally, the vast majority either don’t have charges filed by police or are dismissed at the first hearing.

        I think people are over-thinking the legal side and focus too much on extreme cases that are probably shady to begin with. Or they don’t live in a free state.

      • Giolli Joker

        I think that Alex C. could defend himself with a rolling pin and still an overzealous prosecutor could find plenty of data online to support a “Rambo mentality” theory. 🙂
        Anyway, as Grindstone50k points out, things are not the same everywhere in the world… I’m from Italy, back there if you shoot in a HD scenario you go to court and they confiscate all your guns until you’re proven innocent… i’m pretty sure Texas approach is more common sense based.

  • Hensley Beuron Garlington

    I’m confident in the round considering that our government restricts the SS190 for soft body armor penetration. As for “knock down” power, probably not much, but for mutilating and killing wound channels, maybe consider the SS197SR or SS195LF.

    Knock down power is hard to quantify and dare I say imaginative as you can find YouTube videos of hogs surviving multiple shots from .50 AE and a deer running away after it’s guts are blown out by a .50 BMG.

    This weapon is awesome for cyclist and other places you might want a small gun, but more firepower than a pistol.

    • noob

      would there be a market for a subcompact 5.7mm pistol? or do you really need that barrel to get the results in the pictures above?

      and would a short barrel compact concealable pistol with a long front-to-back dimension on the pistol grip be unergonomic?

  • Sulaco

    With that short a barrel it must have been an SBR?

    • Yes… Hence the title.

      • Sulaco

        Opps need to put glasses on ….

      • Sulaco

        I guess my full thought was that most of us will never be allowed an SBR so for us whats the point?

        • Uhhh… SBRs are legal in like 44 states. You can buy one or make one just like you would a suppressor on a form 1 or form 4. Where did you get the idea that they were restricted?

        • Tim U

          SBRs are legal way more places than they’re not…even loony liberal Minnesota allows them

  • Mini 1.6x

  • Oaf

    A 30 decibel drop (from 158 to 128) when using a 6oz 22 caliber suppressor would not be considered “not at all effective due to the velocity of the round” by a reasonable and educated person. 128 DB is quieter than a suppressed 45.

    • Mazryonh

      Maybe the author was referring to subsonic versions of the 5.7mm round?

      • Blake

        You mean 22LR?

        • Mazryonh

          Never mind, it seems I was mistaken.

    • I throw a Gemtech G5 on this gun every now and again and that son of a gun is still deafening!

      I was exaggerating a bit when I said not at all effective, but as you well know suppressing supersonic ammunition is an act in vain (at least as far as I’m concerned).

  • Mazryonh

    I always did think that the P90 had a distinctly one-size-fits-all design ethic. No room for an adjustable stock, and no way to get another grip for either your trigger hand or off hand (I wouldn’t think the hole for your off hand’s thumb really counts as a “foregrip” either). You wouldn’d be able to use a quad-stack magazine (unless the top holding the sights was removed and replaced with something taller) and obviously a drum mag would be out of the question.

    • Giolli Joker

      I think that magazine capacity is really the least of the issues of this gun…
      (to me actually, it would be one of its best selling points)

      • Mazryonh

        I didn’t say that the P90’s basic 50-round magazine was a liability, per se. It’s just that, by comparison, someone using a CQB-R (a very short-barrelled select-fire AR-15 model) can load in a 100-round drum magazine or some other high-capacity quadstack magazine if that person needs it. The P90 can’t do that.

        • Giolli Joker

          I understand, but the P90 is a PDW, never meant to replace the primary weapon, but designed to offer more firepower than a pistol or SMG to those that are not carrying an assault rifle (vehicle crewmen, mainly).
          Besides, a drum magazine or a quad stack adds a lot in cumbersomeness and weight.
          A PDW is a compromise, surely there are options that offer more firepower in a similar package, but the usually have drawbacks in the fields where the P90 shines.

          • Mazryonh

            The funny thing is, despite the name “Personal Defense Weapon,” to my knowledge they still haven’t been issued to noncombatants or vehicle drivers; they’ve mainly been used as close-assault weapons by special forces, VIP protection, and counter-terrorist forces. It could be some time before we see that happen yet.

          • Giolli Joker

            Yep, you’re probably right on that.
            In all the uses you listed a slim short gun like the P90 appears to be ideal compared to a short AR (or other assault rifle) with a huge magazine.
            I think that the main limitation in the military use is the logistics behind the adoption of a new, additional, caliber…. maybe it’s been evaluated that costs would outweigh benefits.

          • Mazryonh

            Well, when the time came to try and introduce the 5.7mm round as a new standard for PDW platforms, the UN commission said that it was similar enough to the 5.56mm NATO round to allow manufacturing on the same production lines, whereas the 4.6mm round could not be (the standardization was indefinitely postponed when the Germans objected). So apparently they had given some thought to the logistics already when the round existed only as a design.

            I’m still looking forward to seeing just how more intuitive and useful-under-duress a platform like the FN P90 might be compared to a short-barrelled AR-15 in the hands of noncombatant personnel. Have there actually been tests to that end? All I’ve found is the account of Anthony G. Williams (a weapons technology writer) who tried out various SMGs/PDWs at a range and found that the ergonomics of the P90 to be somewhat uncomfortable compared to the other designs he tried.

    • Phil Hsueh

      That’s likely because it’s designed as a PDW and from what I recall reading it was intended to sit on racks with the mag already inserted so that a person could just grab it and go. Although FN has marketed it towards SWAT & spec-ops use its primary purpose is still as a weapon for cooks and mechanics to grab if things go really bad for them.

      • Mazryonh

        Of course, one-size-fits-all isn’t inherently a bad thing (just look at how many conscripts adapted to the M1 Garand). Still, I haven’t heard of the FN P90 being issued to noncombatants (even with the problem of “inside-the-wire shootings” that have sometimes surfaced on the news).

  • mzungu

    Unless them zombies rises up, every semi or select is pretty much “a range queen”.

    • iksnilol


      What are you implying? That semi-auto or full auto guns aren’t useful in day to day life in comparison to other types?

  • Hell if I know. But I could easily land it’s at 300 yards I bet.

  • JSmath

    The copious supersonic crack that comes with 5.7mm makes the use of a suppressor a moot point, is what the author was getting at. Then again, if you’re already paying boutique prices for ammunition, I guess you can always double that up for quiet but combat ineffective subsonic loads.

    • iksnilol

      The supersonic crack is like 135 db or something? Still, it is better to use the suppressor than not. More controllability/less recoil at the very least.

  • JSmath

    IIRC 250 yrds is considered its realistic effective range (looked it up – FN claims 200m or 220yrds with the 10.4″ P90). I’ve read many stories of guys taking PS90s to ranges and making consistent hits out to 400-500 yrds. Hits of lethal nature? Doubt it.

    Note: Over two football field lengths is still pretty damn nice imo.

  • Giolli Joker

    I think that the shootout PS90 vs MWS ION is paramount!

    I’m waiting for it!

  • thedonn007

    What? No .22 win mag comparisons yet? The P90, is one of my dream guns. I would get one, if not for the fact that it would be another caliber that I would have to stock.

  • Tassiebush

    It’d be just the thing for shooting wallabies from the mountain bike.

    • Phil Hsueh

      Or Jaffa, Goa’uld, and Ori troopers.

      • RocketScientist


      • Tassiebush

        Hallowed are the Ori!

  • Anonymoose

    I can’t be the only one who would rather have a select-fire P90 with a 16″ barrel, right?

  • Marty Ewer

    I have several PS90s that I’ve papered as SBRs. They are great little guns. Great accuracy. Low recoil. Everyone loves shooting the PS90 SBRs.

  • phuzz

    “the P90 [looks] like a science fiction throwback”
    That’s probably why they used it on Stargate SG1, I think that was the first time I ever saw one, and was pretty surprised when I realised it wasn’t just a prop.

    • TheSmellofNapalm

      And the Hunger Games

    • Grindstone50k

      I liked how G36s were laser guns in Firefly.

      • Tassiebush

        Bring back firefly!

    • bernardg

      Funny thing, i actually first known this weapon back when i was a kid, reading comic book. I was reading Marvel’s Punisher War Journal (Jim Lee as the artist). On every issue, they introduce young passionate readers with a brief but nifty Punisher’s firearm encyclopedia. One of them is this odd but lovely looking P90. Quite detailed artwork too.

  • WasThere

    This weapon is perfect for killing the enemies of earth.
    Jaffa, Goa’uld, Ori, Replicators, Lucian alliance, Wraith, Genii etc..

  • darthcoder

    My buddy has one (MA restricted 10 rnd magazines grrrr). I’m toying with grabbing one if the stars ever align and I have fun-store spending money again.

    I love this little rifle (16.5″ model). consistently great fun, and it puts the brass right at my feet.

  • I am not forgetting a damn thing. I’m just relaying my personal experiences when it comes to shooting 5.7 suppressed and both handguns and long guns.

  • Lmao!

  • Giolli Joker

    I believe the idea was to give you enough firepower to defend yourself (PDW) and allow you to retreat to the vehicle where you can keep spare magazines. It’s not an assault rifle, but it’s definitely much more than a pistol.

  • Tassiebush

    Alex, is it any trickier than normal to load P90 mags? How are the rounds rotated? Is it a spiral ramp?

    • It is a strange process. Slightly more difficult but not too hard. You just need to know how or you can mess it up (there is even a little diagram on the mag to make sure people are going it right, lol).
      Get your ass to Texas and you can figure it out and blow through as many mags as you want!

  • Tassiebush

    I have pretty much nil experience in wearing mag pouches but a pouch with them orientated horizontally would probably overcome that problem.

  • Mazryonh

    Alex, have you done any ballistic gel testing on the 5.7mm round? I’ve read reports claiming that in combat situations you need too many of those rounds to down an aggressive opponent (assuming you don’t have time to aim for CNS hits).

      • Tassiebush

        Good video!

      • Mazryonh

        Thanks, but I was looking more about gel testing to determine its terminal ballistic performance. I’ve read what’s supposed to be anecdotes from professional users of PDW rounds like the 5.7x28mm that say PDW rounds are rather underpowered in military-grade format compared to short-barrelled 5.56mm NATO weapons. I can give you a link if you’re interested in reading its contents.

        Have people successfully managed to hunt deer-sized game with the PS90? With non-expanding ammunition or with expanding ammunition?

  • DIR911911 .

    would be interesting if they adapted another caliber in this gun , 45 or 9mm versions would get snapped up as fast as they could make them and you could afford to shoot it more.

  • DIR911911 .

    WHAT ?

  • Adam

    I cannot comment on the old post… where do you want the photos posted

    • Tassiebush

      Here I reckon. It’s actually relevant to this thread in a sense being a bullpup trigger mechanism.

      • Adam

        ok…. first, if i was to make this again, i would make a block with a slightly oversize hole for the final bar too sit in…Secondly, if you go down this path, my advice, get a 27 inch finished barrel, have it chambered for 300AAC Blackout, but trim 357 Maximum brass to suit 1.370 then use blackout dies too full length size.. this works perfectly…. If you need the barrel, chamber etc done,let me know. you could also thread the barrel…. If you need any advice along the way, feel free to contact me… I have two guys in New Zealand doing something similar on large Martinis, using my 50 Alaskin reamer with a BMG throat.. they plan on running 6 ogive CBE 900 grain gas check cast bullets.. But those buggers get too run it suppressed…

        • Tassiebush

          Thanks heaps for that. I’m looking forward to getting home to a bigger screen to really check them out properly. I like that wildcat rimmed blackout idea! You’ve made my day! 🙂

          • Adam

            You will love the Bullpup Martini, off hand stability is amazing… And remember, you only need 10 grains of 2205 too make 1070 fps with a 240 grain… If you build it, i will post you down some of my 265 grain soft points too try out on deer and pigs..

          • Tassiebush

            Sounds good .bout the stability. I’ll get onto the search for an action. I checked up on a shot out cadet that I’d hoped might be available but it’s sold.

  • Eddie_Baby

    Don’t have to worry about reloading.

  • Mazryonh

    Why would you need to go for this kind of setup when you could just go with something more conventional? Do a search for the “American Katana,” which is a blog concerning a thought experiment about a PDW in 10mm Auto. The nice thing about its layout (loading from the pistol grip) is that with the right design the PDW can share magazines and ammo with a service handgun.