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A leap in evolution | |||||||||
FN Herstal proves that an effective weapon for personal defence is a matter of ammunition design | |||||||||
| In the small arms world weapons evolve, they do not suddenly burst on the scene. But there have been exceptions, one is the 5.7 x 28mm weapon system from FN Herstal, involving a novel small-arms cartridge but with two state-of-the-art weapons to fire it, the P90® sub-machine gun and the Five-seveN® pistol. The cartridge and the associated weapons have raised many eyebrows among small arms observers not used to sudden innovation in a world dedicated to the gradual development of what already exists. Yet this has not happened to the 5.7 x 28mm system. It has been around for nearly a decade and has gained wide acceptance. The 5.7 x 28mm weapon system has three main components: the SS190 cartridge, the P90 submachine gun and the Five-seveN pistol, but the heart of the system rests with the ammunition. As always, the cartridge projectile forms the weapon within any system, the firearms are merely delivery systems. The 5.7 x 28mm cartridge Ordinary pistol ammunition, other than specially developed armour-piercing rounds, cannot make much impression on most body armours so it is as good as useless in many combat scenarios. What FN Herstal realised as the solution was an interim cartridge between short-range pistol rounds, such as the 9 x 19mm Parabellum, and cartridges such as the Eastern Bloc 5.45 x 39mm and the NATO 5.56 x 45mm, both the latter designed for optimum performance at hundreds of metres. Rather than scale up a pistol cartridge, FN Herstal designers decided to scale down the rifle round. The resultant 5.7 x 28mm combines the assets of small cartridges with a fair measure of the power provided by rifle rounds. A 5.7 x 28mm cartridge weighs only six grams, half the weight of a 9 x 19mm equivalent while its diameter is also much reduced at 7.8mm overall, compared to 10mm for the 9 x 19mm. These reduced weights and dimensions, a cartridge is only 40.5mm long overall, mean an individual can carry more combat- ready rounds without any weight increase, and magazines can accommodate more ammunition.
The 5.7 x 28mm round also produces less recoil so the weapon can be handled and aimed more comfortably, especially when firing bursts. But this is less important than penetration and energy transfer. Small arms projectiles rely on kinetic energy for their effectiveness and it is here that the 5.7 x 28mm scores heavily over conventional pistol ammunition. Part of this is because of the make-up of the projectile for the standard 5.7 x 28mm ball round, the SS190. The bullet has a steel jacket containing a steel core just behind the tip. The bulk of the content behind this is aluminium. The nose is pointed and together with the steel core enables the SS190 bullet to penetrate 48 layers of Kevlar-type protection at 200m at a muzzle velocity of 715m/s. It also can penetrate a standard Kevlar-type combat helmet at the same range. The 5.7 x 28mm round is highly effective against body armour at ranges up to 200m but the ammunition also has a high incapacitation effect. As the bulk of the bullet mass is located in the front of the bullet, once it strikes it tends to tumble, in the process giving up most of its momentum and striking power immediately. This produces a large wound cavity and high-energy transfer; the latter is not dedicated, as is usual, to purely driving a hole through the target. Against most targets the SS190 bullet will remain in the target, even at ranges as low as 10m. There is also the added advantage that once the SS190 bullet proceeds past a range of about 300m, its potential wounding power decreases rapidly. For instance, at 150m the bullet carries an energy level of 232 Joules, more than enough to penetrate armour and cause a significant wound. Yet at 400m that energy level has decreased to 85 Joules, enough to be noticed but unable to penetrate hard targets and cause collateral damage. The SS190 cartridge is not the only member of the 5.7 x 28mm ammunition family. There is also the matching L191 with a tracer element, while the Sb193 is a subsonic cartridge intended for use when sound suppressors are fitted to the host weapon. And various training-type rounds are under development. The P90 submachine gun The outlines of the P90 are ergonomic to a high degree. In technical terms it is a blow-back weapon firing from a closed breech at a cyclic rate of fire of 900rpm; there is also a semi-automatic fire mode. Even with a full 50-round magazine the carry weight is only 3kg while the overall length is a compact 500mm. There is no folding butt so the P90® is always ready for immediate aiming. The magazine stows its 50 rounds horizontally and sideways, situated over the P90 receiver. Only when a cartridge is ready for transfer into the weapon is a round rotated on a magazine ramp into the loading position under spring pressure. The polycarbonate magazine housing is translucent so the contents can be seen at all times. Aiming the P90 is kept simple to provide for those whose firing experience may be limited to short training range sessions. The P90 has an integrated optional sight from Ring Sights of the UK, with no magnification. All a user has to do is place a sighting circle on the intended target and that target will be hit at combat ranges, aided to a large extent by the flat trajectory of the SS190 bullet. Under low light conditions a tritium light source illuminates sighting graticules in the optical sight. Standard night sights can be added if required, as can a red dot sight mounted over the existing sight housing. If the optical sighting system becomes unusable for any reason, simple iron sights are provided. With typical attention to detail, FN Herstal designers have provided iron sights on each side of the optical sight housing for right and left-handed users. Other ambidextrous provisions include a cocking handle on both sides of the receiver while the fire mode and safety switch is located under the trigger ready for operation by either hand. Spent cases are ejected downwards to avoid hitting the shooter, even those firing left-handed. At the end of 1999, FN Herstal introduced a new version of the P90, the P90 TR (triple rail) that features one full length rail that allows the mounting of a wide variety of optical sights and two side rails to take accessories such as tactical lights and external lasers. The Five-seveN pistol As its name implies, the Five-seveN fires the same 5.7 x 28mm ammunition as the P90, carrying over all its various armour-penetration and other combat assets to the pistol configuration. The pistol contains 20 rounds ready for use within a detachable box magazine inside the pistol grip. The Five-seveN pistol is available as a double action model and a single action one. The double action model firing mechanism is arranged so that only a long and deliberate trigger actuation will cause the pistol to fire. The training and ready-use advantages that such a feature can bestow are apparent and in no way make this an unsafe pistol to carry and handle. Five-seveN Tactical, the single action version, was designed to integrate the specific requirements of all those users for whom a pistol is a primary weapon. Weight loaded is only 774 grams for the double action model and 630g for the single action while the overall length is 208mm for both models. The muzzle velocity is reduced slightly to 650m/s. At the instant of firing the Five-seveN is locked using a delayed blow-back action. The muzzle jump is almost non-existent. The Five-seveN accommodates many combat accessories. Although the 5.7 x 28mm weapon system was developed for military applications it has found many other users. A big attraction is that its greatest rival, the 9 x 19mm Parabellum cartridge, is, in design terms, nearly 100 years old. It will be a hard task to overcome the well-entrenched 9 x 19mm lobby because the small arms world is conservative, but FN Herstal is certain it has a winning formula, as any study of the 5.7 x 28 mm weapon system will reveal. © | |||||||||
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Friday, October 08, 2004
Global Defence Review (2000) - A leap in evolution
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