These both are examples of a class of weapon called PDW, Personal Defense Weapon. They exist to provide their operator with a weapon that is always on the user, and hopefully provides a level of performance greater than just a standard handgun. Their design is usually in the beginning intended for non-combat forces or troops who operate in tight quarters such as truck drivers, radio operators, armored vehicle crews, air crews, or anyone who needs a small handy weapon. They are usually not intended to be replacements for assault rifles, battle rifles, or submachine guns. In theory.

The FN P90 stems from research done by NATO in the 1980's that showed that the standard 9mm FMJ bullet fired by pistols being issued to non-com troops would be ineffective against the new generation of body armor starting to come into service in the West and assumed in the Warsaw Pact. This was particularly disturbing since many assumed that the Soviets would attempt to deploy Spetsnaz forces behind the front lines during wartime to disrupt transportation and communication lines. Also without sufficient and constant training it is often hard to effectively use a handguns beyond point blank ranges. Something better was needed. FN's answer was the P90.

Small, light, low recoil, and easy to use the P90 is one of the best designs of its type to go into production. It uses a simple blowback action that ejects the spent cartridge downward for left or right hand use; also it employs an ingenious 50 round translucent magazine that lays flat on top of the weapon. Its polymer thumbhole stock and combination trigger guard/ front handgrip gives it a very Sci-fi look to it. Its sights are simple and intuitive to use. The one bone of contention about its design is its choice of cartridge.

To achieve its low recoil impulse, flat trajectory, generous ammo capacity, and armor penetration performance FN developed a new round for the P90 the 5.7x28mm. When using the SS190 bullet this little round easily met the NATO requirements for armor penetration. What many people were concerned about is whether the round will just zip through the target, or whether it will produce sufficient damage to quickly put a target down. There are vocal forces on both side of the argument who will point to various studies or real world shootings to defend their stand on the 5.7x28mm.

Personally I am ambivalent to the round. I know that it has been used in several real world shootings and so far it appears to have performed very well; however to my knowledge all the shootings I can find involving the 5.7x28mm also have involved SWAT or Special Forces who exercised excellent shot placement and fire discipline. Since do not believe body armor was worn by any of the targets would they have been able to do the same job with just a plain old US M1 Carbine? Will the same results happen to the cook that suddenly finds his base under attack?

The Vz-61 Skorpion was officially adopted by the Czech Army around 1961. It was developed to provide non-infantry troops with a light PDW. Technically it is a type of machine pistol that can be carried in holster just like a standard pistol. It has a light wire stock that permits a steadier platform for firing. With a rate of fire around 850rpm even the optional 20 round magazine can run dry quick, but at least its rate of fire offsets its one main weakness. Its choice of caliber.

While used for decades by European Police the 7.65x17mm, 32ACP, is not a real tiger of a cartridge. Especially in its Geneva complying full metal jacket, FMJ, form. Also I'm not certain how well hollowpoints would feed in it. The one advantage the Vz-61 does have is that the 32ACP is very easy to reduce to subsonic velocities and therefore can used with suppressors fairly easily. This made the weapon popular with some security and special forces during the Cold War. Also the weapons were distributed to various insurgents and terrorist organizations during the 60's, 70's and 80's. The weapon appears to have been rather popular in Africa which might explain how Little Rommel was able get one off the body of one of her tormentors http://www.furaffinity.net/view/894869/ .