I got this little toy, a P90 (technically, it is a PS90).  Shown next to my AK-103 clone for size comparison.  The wife has claimed it as "hers" :)  Being left-eye dominant, I've added a red dot sight with "tall" rings to the side rail so she can shoot it easier.

Vid of the wife shooting is on my Skydrive videos section


There's not really much to these.  They are LIGHT!!!  Extremely portable, even with the 16" barrel.  My wife loves it!  They are bullpup design.  Yes, you can actually fire it single-handed "just like in the movies" and keep it on target.

Since they are such a popular item right now, they are able to be accessorized ad nauseum, and there is a plethora of information.   Accessories for practically any application can be found for these fun little toys! 

There is also a sad group of sycophantic P90 and 5.7 caliber elitists who are convinced God Almighty Himself uses the P90 to Smite the Wicked!  If you encounter these folk, be sure to take their statements about the P90 with a grain of salt, or at least keep your tongue in your cheek.  Try to be polite to them so they won't bite - and whatever you do don't compare the caliber to any other caliber that uses .224 bullets!  :)


5.7x28 Cartridge

The small little 5.7x28 next to a 7.62x39, .223, and .40SW for comparison.  It is a standard .223 bullet (.224 if you like to be technical) and a down-sized case.  A ".223 Short" if you will.  The 5.7x28 is in use in one other FN offering, the Five-Seven pistol.  It normally carries 20 rounds and is a lightweight and easily-wielded pistol.

The 5.7x28 was designed from the ground-up as a Personal Defense Weapon (PDW) round to supplant the 9mm.


Unfortunately, there is a considerable amount of FUD about the capabilities of the small little round.  It was designed for one thing -  to penetrate armor.  It does this.  However it reportedly does NOT have enough mass to maintain the energy to blow people across rooms as you see in Hollywood.  There are reports that it does little to stop a target. 

Most combat evidence is from one of the first combat employments of the P90 during the Peruvian embassy hostage situation from ca. 1997.  Reports from the field indicated the targets had to be "sprayed" for an effective put-down.  Reportedly, the suppressed P90 was carried by point men in the rescue of the Japanese embassy in Lima, Peru. It was used successfully to pierce the body armor and kill the leader of the Tupac Amaru terrorists.  The knock-down power may have been limited if they used a subsonic load, but that information is not available.

Updated info:  Found some pics of the incident.  This one is the best one of the bunch where you can actually see the troops with their weapons.  A curious lack of P90's on display...


This pic was taken from a site talking about a movie being made of the incident - therefore this may be a movie set photo: 

A few reference links about the incident.  More information will be posted here as it is collected:



Additional real-world update:


Experiences with the FN P90

Written by Sandy Wall

"Houston SWAT was involved with the first and only [LEO] lethal engagement with the weapon to date." (2003)

"In the one shooting we had with the P90, the bullet performed well. In fact, the bullet performed exactly as it was designed. The autopsy provided detailed information about the wound cavity and travel of the bullets. None of the 5.7mm rounds fragmented and as far as we can tell, none exited either. The shooting itself was a violent confrontation with many rounds exchanged between the suspect and the react team. The suspect was hit multiple times with both 5.56mm and 5.7mm rounds."

"The 5.7mm ball produces a wound cavity about the size and shape of the best 9mm 115 grain JHP +P+, except the peak occurs at a deeper penetration."


There are reports that the cartridge has enough energy to take down deer-sized game.  Obviously it will be extremely effective as a varmint cartridge on smaller targets such as varmints and possibly even coyote-sized game.  If there was more information about the exact type of ammunition used in the embassy situation, a better comparison of the wound potential could be established.  Unfortunately there just isn't that much Real-World data to gauge its effectiveness against human targets. 


What we do know:  it is a cut-down 5.56x45 round and in fact uses the lighter .224 bullets in 35-40 grains (compare to military 5.56 loads use either 55 grain or 62 grains).  All we can definitively say is that, as a replacement to the 9mm, it achieves its goal as a Personal Defense Weapon platform.  It of course was never intended to be a Main Battle Rifle, which it is not.  Anything else is speculative.  Again from that previously mentioned article:

"The 5.7mm ball produces a wound cavity about the size and shape of the best 9mm 115 grain JHP +P+, except the peak occurs at a deeper penetration."


Curiously, compared to other "shorter" .224 loads, it performs on the lower side of the velocity charts.  Examples include the .221 Fireball, .22 Hornet, etc. which all deliver higher velocities with a slightly longer case.  It could almost be described as a "light" or "short" Fireball round.  Presumably FN wanted a cartridge that was "good enough" to meet their design goals and these cartridges, while ubiquitous, would not help them sell more ammo :)  Regardless, the cartridge does what it was designed to do and should be here to stay.



Other Platforms

An interesting prototype upper for the AR platform that utilizes the P90 magazine was built but never brought past the prototype stage.  Now there is an upper in production.  Info I have collected about the uppers can be found here






Accurate Arms and Ramshot have published reloading data! 

Ramshot is purportedly the supplier to FN but this is unconfirmed.

I believe this is the same data from both companies - I believe they are affiliates?  The documents appear to contain part of the same data. 




Update 2012 - it took them 5 years, but Lyman has published load data in their #49 manual.  There still isn't much reloading information but additional published reloading data will be linked when it arrives.  I would STRONGLY recommend AGAINST "home-brew" reloading formulas published on various forums.  There are reports that at least one person has actually BLOWN APART their Five-Seven pistols using "home brew" reloading formulas they downloaded and followed.  Seriously... don't do it!  There may be other happenings, but there has only ever been one unfortunate honest soul that confessed to it!  :) 

This round is very critical in dimensions.  As a blowback system, the P90 design relies on headspace and case dimensions for safe and proper function.  Improperly sized rounds could cause an out-of-battery discharge as with a Glock.  This seems to be the most common reason for failures, however there has not been any published deep-level analysis of the destroyed weapons to validate this.

I can not stress enough that OFFICIAL RELOADING MANUFACTURERS DATA should be the only source that is consulted for reloading purposes.  Obviously, reload-induced failures would not be a warranty item.  Yes, there has been some reload testing by brave individuals who are making educated guesses, but remember that just because you can do something doesn't mean you should - if some "expert" on the Interweb said they can get X velocity out of Y load and it works for them doesn't make that load safe!  Considering the location of the bullpup to your body when firing, I cannot overstate the need for caution when using reloads!  The manufacturer won't honor warranty claims due to ammunition failures, so "Buyer Beware"... the cost to replace a frame is substantial.   Hospital costs are even worse.  If you choose to reload, stick with the published data.





The magazine "conversion" due to the fact that FN ships a factory 50-rounder as a 30- or 10-round mag with a shim for those states that do not allow full magazine capacity. 

You can cut this shim down since just the end is necessary.  It takes probably 5 minutes to disassemble, cut the shim, and reassemble.  I used a dremel but you could use a hacksaw. 


Slings.  There are about a bazillion different slings.  This is a standard "single-point" that I will probably get or build as I did with my G36 sling.  You can even get the "StarGate" carry harnesses.  Seriously.  And they actually look like a good carry harness, considering.


Aftermarket Front Sling Mount:



Brass catcher.  Since I plan to reload, I'm going to be needing one of these.  I plan to fabricate one from some material I have... can't justify the exorbitant expense of aftermarket brass catchers.




My "budget" rail project.  The wife can't find the factory sight due to her left-eye dominance.  I mounted a red dot so she can hopefully enjoy shooting instead of hunting for the sight picture.  The rail is a generic rail I got with a Tapco part, perhaps the FAL scope rail.  Simply cut to shape and drilled for the flush-mount screws. 

Update: this works!  The rail is extremely sturdy and "simply works".  The wife is happy :)  These pics are before I painted the cut end...



Stargate Sling

For when you have to kick alien butt...

This design is a surprisingly utilitarian design as it is completely hands-free and not as cumbersome as a 3-point sling solution since you don't have to wrap the sling around your head - just unclip to release.  Weak-side shooting is easily performed.  Note there are two ways to carry - the 2nd way doesn't use straps under the arms, so less hassle.  In fact the 2nd way (no under-arm wraps) appears to be a simple single-point sling that is cinched down to make a small "around the neck" loop. 


Aftermarket copies





Additional Slings and Magazine Pouches