FN 5.7×28mm

Development The 5.7×28mm cartridge was designed in response to NATO requests for a replacement for the 9×19mm Parabellum cartridge. According to the NATO requirement, the new cartridge was to have greater range, accuracy, and terminal performance than the 9×19mm cartridge. Additionally, it was to be capable of penetrating body armor. U.S. Patent 5,012,743 ("High-Performance Projectile") was received in 1991. When fired from the FN P90, the 5.7×28mm SS190 can penetrate the NATO CRISAT vest or a Level IIIA Kevlar vest at a range of . The SS190 uses a shorter projectile with a mass of , which has, when fired from the P90, a muzzle velocity of roughly . The shorter length of the SS190 projectile allows it to be more conveniently used in the 5.7×28mm FN Five-seven pistol, which was also being developed at that time. NATO evaluation In 2002 and 2003, NATO conducted a series of tests with the intention of standardizing a PDW cartridge as a replacement for the 9×19mm Parabellum. After being met with controversy regarding its alleged armour-piercing abilities, the SS192 variety was discontinued in the same year, and in 2005 the SS196SR variety was introduced using a 2.6 g (40 grain) Hornady V-Max projectile. The SS196 was also quickly discontinued in favor of the newer SS195LF and SS197SR varieties, which are currently offered to civilian shooters for use in 5.7×28mm firearms, followed by the SS198LF variety, which is currently produced but is restricted by FN to military and law enforcement customers. Starting in 2012, Federal began producing a new 5.7×28mm round for civilian shooters, designated the AE5728A. ==Design details==

The 5.7×28mm cartridge was designed by FN Herstal specifically for use in the FN P90 personal defense weapon and FN Five-seven pistol. Excel Arms has developed four firearms chambered in 5.7×28mm, Since the 5.7×28mm cartridge also has a relatively small diameter, a relatively high number of cartridges can be contained in a magazine. The cartridge has a loud report and produces considerable muzzle flash (when fired from a pistol), but it has roughly 30 percent less recoil than the 9×19mm cartridge, improving controllability. Due to its high velocity, the 5.7×28mm also exhibits an exceptionally flat trajectory. One of the design intents of the SS190 variety of this cartridge was that it have the ability to penetrate Kevlar protective vests—such as the NATO CRISAT vest—that will stop conventional pistol bullets. and an effective range of and a maximum range of when fired from the Five-seven. However, some are skeptical of the bullet's terminal performance, and it is a subject of debate among civilian shooters in the United States. The lightweight projectile also poses less risk of collateral damage in the event of a miss, because it loses much of its kinetic energy after traveling only , whereas a conventional pistol bullet such as the 9×19mm retains significant energy beyond . This range exceeds the engagement distances expected for the 5.7×28mm cartridge's intended applications, so the cartridge's limited energy at long range is not conversely considered to be disadvantageous. Since the 5.7×28mm SS190 projectile does not rely on fragmentation or the expansion of a hollow-point bullet, the cartridge (and 5.7×28mm firearms) are considered suitable for military use under the Hague Convention of 1899, which prohibits the use of expanding bullets in warfare. FN's 5.7×28mm cartridge cases are covered with a special polymer coating for easier extraction with the PS90 carbine due to the high chamber pressures and lack of case tapering. In addition, this coating ensures proper feeding and function in the magazines. ==Cartridge dimensions==

, 5.7×28mm, .30 Carbine The 5.7×28mm has a cartridge case capacity of 0.90 ml (13.85 grains H2O). Americans define the shoulder angle at alpha/2 ≈ 35 degrees. The common rifling twist rate for this cartridge is 1:228.6 mm (1:9 in), 8 grooves, Ø lands = 5.53 mm, Ø grooves = 5.62 mm, land width = 1.63 mm and the recommended primer type is small rifle. According to the official C.I.P. (Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives) rulings, the 5.7×28mm can handle up to Pmax (the nominal maximum) piezo pressure. In C.I.P. regulated countries, every rifle cartridge combination has to be proofed at 125% of this maximum C.I.P. pressure to be certified for sale to consumers, referred to as "PE". This means that 5.7×28mm chambered arms in C.I.P. regulated countries are currently (2018) proof tested at PE piezo pressure. Despite the relatively high maximum pressure, the bolt thrust of the 5.7×28mm is on a similar level when compared with traditional service sidearm cartridges. == Specifications ==

Fired from the longer barrel of the PS90, the muzzle velocity of SS195LF is roughly faster, and the muzzle velocity of SS197SR is roughly faster. ==Cartridge types==

;SS90 prototype :The SS90 was an early prototype round used only in the earliest examples of the P90. It used a lightweight 1.5-g (23 grain) full metal jacket bullet with a polymer core, which it propelled at a muzzle velocity of roughly 850 m/s (2,800 ft/s). The SS90 was abandoned in 1994 in favor of the heavier and shorter SS190 projectile. The SS190 has been manufactured with a plain, black, and a black-on-white tip color. It is classified by the ATF as armor-piercing (AP) handgun ammunition, and its sale is currently restricted by FN to military and law enforcement customers. is a tracer cartridge designed for easier bullet spotting in dim light. The SB193 can be identified by its white tip color. and it is distributed in the United States by Federal Cartridge Company. ;Handloading :Handloading is possible with 5.7×28mm ammunition, and bullets are widely available due to use in .223 Remington and 5.56×45mm NATO cartridges. Handloaders have noted that the 5.7×28mm cartridge is very sensitive to small changes in powder charge or overall length (OAL) with a bullet inserted. Bullets weighing 2.6 g (40 grains) or less are recommended for optimal use in 5.7×28mm applications, but the 228.6 mm (1:9 in) rifling twist rate (distance the bullet must travel to complete one full revolution) used in the firearms' barrels will stabilize bullets weighing up to 4.5 g (70 grains). ==Platforms==