The P90 is a highly accurate, bullpup style submachine gun that originated in Belgium.
Sons of Liberty
The FN Herstal P90 submachine gun was the weapon of choice used by Solidus Snake during the Big Shell Incident. He used it to great effect against unmanned RAY units and to execute Olga Gurlukovich. The weapon was also a part of the equipment worn by the Arsenal Tengu.
The P90 was the standard issue weapon for the Haven Troopers under Liquid Ocelot's Outer Heaven. The lightweight build and compact size made the submachine gun the ideal choice for the agile units. The P90 was also wielded by Laughing Octopus of the Beauty and the Beast Unit.
Behind the scenes
Metal Gear Solid 2: Sons of Liberty
It's of worthy note to mention that Solidus Snake seemed to use a very different ammunition type both from those used by the Tengu commandos and from normal P90 ammunition. His rounds combined an enhanced armor piercing ability with an apparent explosive incendiary effect; demonstrated by first piercing the head-piece armor of the mass production Metal Gear RAYs and then exploding, inflicting a critical amount of damage to multiple units with only a few rounds needed in each to accomplish this task.
By comparison, Raiden fought a number of the same sort of RAY units using anti-aircraft weaponry, and, only after multiple direct shots, was able to force a unit into retreat, rather than bring about a total and immediate destruction.
This sort of effect far outperforms the SS190 cartridge; the proprietary 5.7x28mm round used in both the P90 Personal Defense Weapon (PDW) and the Five-seveN pistol. The primary function of the SS190 is to penetrate body armor worn by personnel and not to effectively engage and destroy large vehicles.
Metal Gear Solid: Portable Ops Plus
- "A new concept light firearm developed for soldiers who cannot carry full-size light arms, such as aircraft crews and rear support units. The P90 is designed to provide enough firepower to pierce helmets and bulletproof armor at a range of around 200 metres. The chamber is behind the pistol grip in bullpup style, but the cartridge is ejected downward, allowing it to be fired the same way by left- and right-handed users. Fires 5.7mmx28 ammo. Holds 50 rounds."
- ―P90 description in Metal Gear Solid: Portable Ops Plus
Players may favor the P90 over other sub-machine guns due to its high capacity of 50 bullets per magazine.
Metal Gear Solid 4: Guns of the Patriots
- " A small self-defense firearm developed to provide rifle-grade firepower to vehicle crews, rear support units, and others whose primary missions do not involve carrying service rifles.
Currently employed as a close-range offensive weapon by many police and Army Special Forces units, it uses newly developed 5.7mm x 28 ammo with high penetration power. The plastic magazine holds a hefty 50 rounds.
An easy-to-handle weapon with excellent penetrative power and low recoil."
- ―P90 description in Metal Gear Solid 4: Guns of the Patriots
The P90 features as a playable weapon in Metal Gear Solid 4: Guns of the Patriots. It accepts a sound suppressor, as well a visible laser sight and/or flashlight. Notably, it is one of the weapons that may be used in the motorcycle chase after Solid Snake meets Big Mama.
Remember to fire in short bursts, as the P90's rate of fire is extremely high and will dry the magazine in 3.5 seconds; this will also increase its accuracy. Due to its superior penetration, the P90 is also one of the fully automatic weapons that is particularly effective against Haven Troopers. This penetration is not reduced by the suppressor attachment, a perfect weapon for engaging Haven Troopers silently in close range.
In Metal Gear Online, the P90 is a well-balanced SMG. It possesses a high accuracy and rate of fire, but is offset by low damage and high recoil when firing on fully automatic. Nonetheless, a skilled player can take advantage of its high magazine capacity and accuracy at closer ranges to score multiple headshots on foes in quick succession. It is also capable of mounting a silencer, laser sight, and flashlight on its rails and barrel.
Metal Gear Acid
The P90 features as a weapon card in Metal Gear Acid.
The weapon card number is 019 and is a EQUIP-only card. The weapon attacks in a 4-square T-shaped pattern which is excellent for taking down multiple assiliants with one sweep and dealing heavy damage to armored targets. It also adds FALL to the damage so it dosen't require a 'Add Fall' card to attach. Equipped P90s that counter-attacks do not use the Area Attack or those equipped with the 'Attack 1 Enemy' Card.
As it is a Equip-only card, it can be saved as either a Counter Card or used with the Five-Seven, or another P90 Card, to attack enemies directly.
The P90 is also fielded by heavily armored guards. Using cards that stop FALL would be recommended when facing these guys.
Use this card when facing multiple enemies as the area attack method of the P90 can be cruicial in clearing the immediate area of adversaries. The FALL effect is also nice especially when knocking enemies out.