FN P90 Misc

Manufacturer: Fabrique National, Herstal, Belgium
Type: Selective fire submachine gun
Caliber: 5.7X28mm SS 190
Operation: Blowback
Weight: 6.6 lbs., loaded
Overall Length: 19.7 inches
Barrel Length: 9.5 inches
Magazine Capacity: 50 rounds
Rate of Fire: 200 rpm on automatic
Muzzle Velocity: 2,330 fps
Effective Range: 200 meters

The Weapon

The FN P90 submachine gun, along with the FiveseveN pistol, were designed to give military personnel a system of weapons that were smaller than conventional rifles and carbines, but retained the ability to penetrate soft armor and combat helmets. The P90 is largely constructed of polymers, which contribute to its light weight and unique profile. At less than twenty inches in overall length, the weapon is compact and maneuverable, with controls and straight down ejection that make it entirely
ambidextrous.

A revolutionary feature of the P90 is the see-through, double column, polymer magazine. The magazine rests atop the weapon, parallel to the barrel, as can be seen in the above picture. The cartridges are actually held perpendicular to the barrel's axis, bullets pointing toward the operator's left, and each round is rotated 90 degrees for chambering. In spite of the compactness of the design, the magazine holds 50 rounds of 5.7mm ammunition.

This submachine gun is equipped with a 1X optical sighting system with low light reticle, and has iron sights on each side of the scope, for left- or right-handed shooters. There is an optional built-in laser sight, and a rail to mount flashlights or lasers on either side of the optical sight. A brass catcher is available that snaps onto the ejection port at the bottom of the weapon. It has a capacity of 100 empty cases.

The P90 can be fitted with a suppressor that is 7.9 inches long and 1.6 inches in diameter. Constructed of steel and aluminum, it weighs only 0.88 pounds. When used in conjunction with the
Sb 193 subsonic ammunition, a 30 db reduction in sound is claimed.

The Ammunition

The 5.7X28mm cartridge is something of an intermediate between the 5.56X45mm and 9X19mm NATO rounds. This diminutive round is only 1.6 inches in overall length, with a case diameter that is slightly more than half that of the 9mm. The ammunition is only about half the weight of the 9mm as well- a mere 93 grains per ball round. Recoil impulse is on par with .22 Rimfire rounds, even with a chamber pressure that exceeds 49,000 lbs./psi.

There are currently five types of ammunition available in 5.7X28mm: ball, tracer, subsonic, blank, and dummy. The SS 190 ball cartridge is topped with a 31 gr. steel-jacketed, dual core projectile. A steel penetrator is located in the tip of the bullet, as in the 5.56mm SS 109 projectile, but the aft portion is filled with aluminum, instead of the more conventional lead. Muzzle velocity is about 2,330 feet per second out of the P90 SMG, which results in a muzzle energy of about 374 ft-lbs.

The SS 190 bullet was designed to penetrate up to Level IIIA soft body armor. Testing indicates that it will barely penetrate a 12 inch block of ballistic gelatin, and will penetrate less than 10 inches of gelatin after defeating a ballistic vest. Though some 15 countries use the P90 and FiveseveN systems, the weapon has apparently been used in actual combat only once: six suppressed P90's were used by Peruvian forces during the raid on the Japanese embassy. Unfortunately, results are classified.

Enter the IWBA

The January, 2000, issue of the American Rifleman magazine contains a letter written by Dr. Martin L. Fackler, President of the International Wound Ballistics Association. In his correspondence, Dr. Fackler blasts the magazine for publishing a previous article which insinuated that the 31 gr. SS 190 projectile produces a wound cavity similar to the 62 gr. SS 109 bullet used in the M16A2. Calling such a comparison "an absurd exaggeration," he noted that the P90 bullet does not match the "wounding capacity of a well-designed, expanding 9mm handgun bullet." The doctor further stated that the 5.7mm projectile is about equal to the .22 WMR in actual wound potential.

tangofox's Take

For better or worse, this author believes the P90 to be a harbinger of things to come. Polymers, bullpup stocks, small-caliber ammunition, optical sights, and ambidextrous operation are here and here to stay. Say goodbye to wood, leather, conventional layout, and iron sights (except as backups) for military arms of the future. Illuminated reticles are becoming the rule, rather than the exception, and this is a good thing. At least most countries are adopting weapons for the next generation that do not require batteries, unlike the United States.

In an admittedly apples and oranges comparison, the muzzle energy of the 5.7mm ball round (374 ft-lbs.) is about equal to that of the 9mm NATO and .45 ACP. Since projectile weight and muzzle velocity for the Sb 193 subsonic round were not available, the author used the 31 gr. weight of the SS 190 bullet and the arbitrary assignment of 1000 fps as a (barely) subsonic muzzle velocity to obtain a muzzle energy of only 68.9 ft-lbs.! A 40 gr. bullet would raise energy by 20 foot pounds, but that is still less than a .22 Long Rifle when fired from a rifle-length barrel.

Is the little 5.7X28mm round up to the task? That is the $64,000 question. There are wildly differing accounts of the cartridge's wounding potential. One would think that if the P90 had been a great success in the Japanese Embassy raid, Fabrique National would be trumpeting the results to generate more sales. But, the world must wait until the weapon sees more combat use to see if this is a revolution in small arms ammunition or a flash in the pan.